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The Ultimate Chicago Rooftop Guide: 70 Open-Air Bars, Lounges And Restaurants

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CHICAGO — As Chicago’s weather gets warmer and the days get longer, locals and visitors can make the most of the season at the city’s open-air rooftops and terraces.

Whether you’re looking to grab a bite to eat high above the city’s bustling Downtown streets, lounge by Lake Michigan at a beach club, grab a casual drink at an Irish sports bar, enjoy a night out on the town or hide away in verdant garden terraces, there’s something for everyone.

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Here are 70 open-air bars, lounges and restaurants in Chicago:

Beverly/Morgan Park

Open Outcry Brewing Co.

10934 S. Western Ave.


11 a.m.-10 p.m. Tuesday-Thursday, 11 a.m.-11 p.m. Friday-Saturday, 11 a.m.-9 p.m. Sunday


South Side brewery Open Outcry boasts a rooftop beer garden through the spring, summer and fall with deck chairs, couches, music and food and drink service.

Bronzeville/Near South Side

VU Rooftop Bar, 133 E. Cermak Road. Credit: Provided

VU Rooftop Bar

133 E. Cermak Road


4 p.m.-midnight Monday-Thursday, 4 p.m.-1 a.m. Friday-Saturday, 4 p.m.-11 p.m. Sundays


At 22 stories high, VU Rooftop features city vistas, three bars, two patios, fire pits and retractable windows for cold seasons. Visitors can sip cocktails and enjoy sweeping views of Downtown and Lake Michigan.


The Woodlawn, a Chatham community hub with a rooftop space, at 1200 E. 79th St. Credit: Provided

The Woodlawn

1200 E. 79th St.


3-10 p.m. Tuesday-Thursday, 11 a.m.-11 p.m. Friday-Saturday


Launched in 2018, The Woodlawn in Chatham is a restaurant, internet cafe, event space, podcast studio, rooftop and more — all in one. This innovative community hub offers rooftop yoga and gardening, and residents can rent out the open-air space for $200 per hour for up to 30 people.

Downtown/The Loop

Hyatt Centric’s rooftop bar, Aire, 100 W. Monroe St. Credit: Provided

Aire Rooftop Bar

100 W. Monroe St.


3-11 p.m. Monday-Thursday, 3 p.m.-midnight Friday-Saturday, 1-9 p.m. Sundays


Sitting 24 stories high atop the Hyatt Centric, this rooftop bar offers bird’s-eye views of the city and serves up cocktails, wine, beer and shareable platters.


122 W. Monroe St.


5-10 p.m. Tuesday-Thursday, 5-11 p.m. Friday-Saturday


Named after an Argentinian tango move, Boleo offers a Latin American-inspired menu reminiscent of Peruvian and Argentinian street food. The 15th-floor rooftop in The Loop sits atop The Kimpton Gray Hotel. With a retractable roof, you can visit regardless of the season.

Cerise Rooftop

203 N. Wabash Ave.


4-10 p.m. Monday-Wednesday, 4 p.m.-midnight Thursday, 4 p.m.-2 a.m. Friday, 2 p.m.-2 a.m. Saturdays, 2-10 p.m. Sundays


Grab dinner and drinks at this indoor-outdoor rooftop in the Virgin Hotel, where DJs spin records through the evening. At 26 stories high, you also get a fantastic view of the city.

Château Carbide

230 N. Michigan Ave.


5-11 p.m. Monday-Thursday, 5 p.m.-midnight Fridays, 3 p.m.-midnight Saturdays, 3-11 p.m. Sundays


Château Carbide sits 24 stories above Chicago’s Magnificent Mile, offering a “botanical-driven” cocktail bar, absinthe-focused drinks, craft cocktails and live music on Fridays and Saturdays. Its menu features upscale bites, weekend French flatbreads and decadent small plates by its executive chef.

The Chicago Athletic Association’s Cindy’s Rooftop, 12 S. Michigan Ave. Credit: Provided

Cindy’s Rooftop

12 S. Michigan Ave.


11 a.m.-11 p.m. Monday-Thursday, 11 a.m.-midnight Fridays, 10 a.m.-midnight Saturdays, 10 a.m.-11 p.m. Sundays


With an open-air terrace, restaurant and bar, Cindy’s offers an extensive cocktail menu, seasonal cuisine and panoramic views of the city year-round. It’s perched atop the historical Chicago Athletic Association, 13 stories above ground.

LH Rooftop

85 E. Wacker Drive


11 a.m.-midnight daily


At 22 stories high, you’ll get unbeatable views of the city and the Chicago River from the LondonHouse rooftop. The tri-level space has indoor and outdoor seating, where visitors can enjoy American cuisine and cocktails.

NoMI Garden

800 N. Michigan Ave.


11 a.m.-11 p.m. Monday-Friday, 10 a.m.-11 p.m. Saturday-Sunday


A sophisticated breezy rooftop seven floors above Michigan Avenue, NoMi serves up flatbreads, hearty side dishes, sushi, cocktails and more.

Offshore is the nation’s largest rooftop, located at 1000 E. Grand Ave. Credit: Provided

Offshore Rooftop

1000 E. Grand Ave.


11 a.m.-10 p.m. Sunday-Thursday, 11 a.m.-11 p.m. Friday-Saturday


Did you know the world’s largest rooftop is at Navy Pier? With 36,000 square feet of indoor and outdoor space, this multi-seasonal restaurant and bar offers views of the city’s iconic skyline and Lake Michigan.

Raised | An Urban Rooftop Bar

1 W. Upper Wacker Drive


4-11 p.m. Monday-Thursday, 3 p.m.-midnight Friday-Saturday


On the corner of State and Wacker just steps away from the Red Line, Raised is a third-floor rooftop bar offering an impressive view of Chicago’s cityscape and the Chicago River. The venue offers cocktails and wine, as well as twists to classic American fare — like barbecue chips, truffle frites, spring rolls, bacon-wrapped pickle spears and more.

Rosebud Randolph

130 E. Randolph St.


11 a.m.-9 p.m. Monday-Thursday, 11 a.m.-10 p.m. Fridays, 9 a.m.-10 p.m. Saturdays, 9 a.m.-9 p.m. Sundays


Just steps away from Millennium Park, tri-level restaurant Rosebud on Randolph features a rooftop patio amid the city’s skyscrapers.

ROOF On theWit

201 N. State St.


2-10 p.m. Mondays, 4-11 p.m. Tuesdays, 4-11 p.m. Wednesdays, 4 p.m.-1 a.m. Thursdays, 4 p.m.-2 a.m. Fridays, 11:30 a.m.-2 a.m. Saturdays, 1 p.m.-7 p.m. Sundays


With skyline views from 27 stories above ground, theWit’s rooftop has been named one of the top three rooftop bars in the world by Travel + Leisure. It serves up hand-crafted cocktails and cuisine and regularly hosts DJs, acoustic music series and live runway shows.

Shanghai Terrace

108 E. Superior St.


Lunch: 11:30 a.m.-2:30 p.m. Friday-Sunday. Dinner: 5-10 p.m. Sunday, Wednesday-Thursday, 5-11 p.m. Friday-Saturday


In The Peninsula Hotel Chicago is a Chinese restaurant serving contemporary iterations of Shanghainese, Cantonese and Sichuanese dishes. Alongside indoor dining spaces is a chic outdoor terrace lined with greenery.

Starbucks Reserve Roastery

646 N. Michigan Ave.


8 a.m.-8 p.m. Monday-Thursday, 8 a.m.-9:30 p.m. Friday-Sunday


Above four stories of coffee and cocktail bars, bakeries and cafes is the Starbucks Reserve Roastery’s fifth-floor rooftop. Overlooking Downtown’s bustling Michigan Ave, the open-air terrace is open seasonally as weather permits.

Terrace 16

401 N. Wabash Ave.


7 a.m.-11 p.m. daily


Trump International Hotel and Tower’s 16th-floor dining experience features an indoor bar and dining room, plus a 200-seat outdoor patio overlooking Downtown and the Chicago River.

Upstairs At The Gwen

521 N. Rush St.


Find varying breakfast/brunch, lunch/dinner/cocktail and bar hours here. The terrace closes 11 p.m. daily.


This fifth-floor, art deco-inspired rooftop offers skyline vistas and sunrise-to-sundown dining with breakfast, brunch, lunch, dinner and cocktail menus. You can enjoy the open-air terrace on hot, sunny afternoons in the summer, but it also transitions into the winter with fire pits, warm drinks and curling.

The Ivy Hotel’s 16th floor rooftop, Sky Terrace, 233 E. Ontario St. Credit: Provided

Sky Terrace

233 E. Ontario St.


4-10 p.m. Monday-Thursday, 2-11 p.m. Friday-Saturday, noon-8 p.m. Sundays


On Ivy Hotel’s 16th floor, you’ll find a rooftop lounge with light bites, like Italian flatbread and grilled shrimp street tacos, as well as craft cocktails and scenic views of Downtown.

Streeterville Social

455 N. Park Drive


4-11 p.m. Monday-Thursday, 4 p.m.-midnight Fridays, noon-midnight Saturdays, noon-11 p.m. Sundays


Serving up a globally inspired seasonal menu and handcrafted cocktails, the Loews Chicago Hotel’s Streeterville Social also hosts a variety of events on its third-floor terrace. There are social hours, We Drink Pink nights, live music evenings, trivia nights and tailgates.

Z Bar

108 E. Superior St.


4 p.m.-midnight Monday-Thursday, 2 p.m.-1 a.m. Friday-Saturday, 2 p.m.-midnight Sundays


The Peninsula’s luxurious rooftop lounge, Z Bar, features city views, an extensive menu of booze and a variety of global cuisines, from tuna tartare and daikon frites to Cajun crab and caviar potato bites.

Hyde Park

The Promontory, 5311 S. Lake Park Ave. West. Credit: Provided

The Promontory Rooftop Terrace

5311 S. Lake Park Ave. West


Open during select events.


A space celebrating Hyde Park’s musical legacy and community, The Promontory is a music venue and cultural hub with a stunning rooftop. Check out upcoming shows and parties online.


The Piggery Chicago, 1625 W. Irving Park Road. Credit: Provided

The Piggery Bar & Restaurant

1625 W. Irving Park Road


11 a.m.-9 p.m. Monday-Thursday, 11 a.m.-10 p.m. Fridays, 10 a.m.-10 p.m. Saturdays, 10 a.m.-9 p.m. Sundays


Sports bar The Piggery is a great place to catch a game on a big screen. The family-friendly venue prides itself on its Cuban sandwich, bottomless brunch on weekends and an open-air rooftop deck.

Lincoln Park/Old Town

Castaways Beach Club along North Avenue Beach is a popular rooftop to catch the annual Air & Water Show. Credit: Provided

Castaways Beach Club

1603 N. Lake Shore Drive


11 a.m.-9 p.m. Sunday-Thursday, 11 a.m.-10 p.m. Friday-Saturday


Embrace Summertime Chi while lounging on Castaways Beach Club’s boathouse bar and grill, which features an open-air deck overlooking Lake Michigan.

Harvest At Lakeshore Sport & Fitness

1320 W. Fullerton Ave.


4-9 p.m. Wednesday-Friday, 11 a.m.-3 p.m. and 4-9 p.m. Saturdays, 11 a.m.-3 p.m. Sundays


Harvest is a full-service restaurant and bar with indoor and al fresco dining options. Its rooftop overlooks the Chicago skyline and is open to members and non-members.

Joe’s On Weed Street

940 W. Weed St.


5-11 p.m. Thursdays, 8 p.m.-2 a.m. Fridays, 2 p.m.-2 a.m. Saturdays, 2-10 p.m. Sundays


For football fans and country music lovers, Joe’s on Weed Street is the place. The bar and music venue has dozens of TVs and hosts a variety of spring and summer events on its rooftop bar and patio, including live concerts, doggie happy hours and more.

Sully’s House Bar

1501 N. Dayton St.


5 p.m.-midnight Wednesday-Thursday, 4 p.m.-2 a.m. Fridays, 1 p.m.-2 a.m. Saturdays, noon-10:30 p.m. Sundays


Sully’s House is a casual Irish sports bar with a main bar area, lounge and dining room. It also features two open-air spaces: a second-floor private bar that guests can reserve, and rooftop deck with couches and TVs. Guests can enjoy dozens of beers, including more than 20 on tap and 30 in bottles, and comfort food like wraps, burgers, tacos, wings and pizza.

The J. Parker

1816 N. Clark St.


11 a.m.-11 p.m. Monday-Thursday, 11 a.m.-midnight Friday-Saturday, 11 a.m.-10 p.m. Sundays


Sitting on the 13th floor of the Lincoln Hotel, this rooftop bar and restaurants offers views of Lake Michigan, Downtown and the Lincoln Park Zoo. It’s also open year-round, with a retractable glass roof for colder days.

Utopian Tailgate

1608 N. Wells St.


4-11 p.m. Monday-Tuesday, 4 p.m.-midnight Wednesday-Thursday, noon-1 a.m. Friday, 11-2 a.m. Saturdays, 11 a.m.-10 p.m. Sundays


At Pipers Alley Mall in Old Town, rooftop deck Utopian Tailgate lives up to its name with cornhole, drinking games, disco dance parties, super-sized Jenga, beer coolers and more.

Gene’s Sausage Shop & Delicatessen, 4750 N. Lincoln Ave. Credit: Provided

Lincoln Square

Gene’s Sausage Shop & Delicatessen Rooftop

4750 N. Lincoln Ave.


11 a.m.-8 p.m. Thursdays, 11 a.m.-8 p.m. Friday-Saturday, 11 a.m.-4 p.m. Sundays


Gene’s European-style beer and wine garden isn’t your average Chicago rooftop. The menu features smoked sausages and bratwurst cooked on an open-wood grill, potato salad, mixed greens and more, plus rotating beers on tap and wines by the glass. As long as the weather permits, Gene’s opens its rooftops three days per week through the summer.

Logan Square/Palmer Square

BiXi Beer

2515 N. Milwaukee Ave.


3-11 p.m. Monday, Wednesday-Thursday, 3 p.m.-midnight Friday, 11 a.m.-noon Saturdays, 11 a.m.-8 p.m. Sundays


A modern, Asian-inspired brewpub, this Logan Square establishment serves up Chinese, Korean and Vietnamese cuisine and original beer on its rooftop terrace.

Lonesome Rose

2101 N. California Ave.


11 a.m.-11 p.m. Monday-Thursday, 11 a.m.-midnight Fridays, 10 a.m.-midnight Saturdays, 10 a.m.-10 p.m. Sundays


Tex-Mex bar and restaurant Lonesome Rose is known for its plant- and light-filled open design, which extends to its rooftop patio. The Logan Square staple offers breakfast tacos, queso, nachos, burritos, margaritas and more. Lonesome Rose unveiled a second location in Andersonville last year, but it doesn’t have a rooftop space.

Masada’s rooftop, 2206 N. California Ave. Credit: Provided


2206 N. Milwaukee Ave.


4 p.m.-midnight Tuesdays, 4 p.m.-2 a.m. Wednesday-Friday, 9a.m.-3 p.m. Saturdays, 9 a.m.-2 p.m. Sundays


Masada is a popular Logan and Palmer Square nightclub. Complete with a lush rooftop patio and garden, the Middle Eastern venue regularly hosts dance parties, live DJs and music events.

The Black Lion

2434 N. Milwaukee Ave.


5 p.m.-2 a.m. Fridays, 5 p.m.-3 a.m. Saturdays


Neighborhood bar The Black Lion serves up Latin American spirits and cockails alongside regular live music shows.


Sidetrack The Video Bar’s rooftop, 3349 N. Halsted St. Credit: Provided/Sidetrack Facebook


3349 N. Halsted St.


3 p.m.-2 a.m. Monday-Friday, 1 p.m.-3 a.m. Saturdays, 1 p.m.-2 a.m. Sundays


This multi-level gay bar hosts a wide variety of events celebrating the LGBTQ+ community. Visitors can lounge on the rooftop while sipping specialty cocktails or plan a visit for one of Sidetrack’s dance parties, “RuPaul’s Drag Race” screenings, storytelling sessions and other entertainment programs.

Norwood Park

The Garage Bar & Sandwiches, 6154 N. Milwaukee Ave. Credit: Provided

The Garage Bar & Sandwiches

6154 N. Milwaukee Ave.


4 p.m.-midnight Tuesday-Thursday, 4 p.m.-1 a.m. Fridays, noon-2 a.m. Saturdays, noon-10 p.m. Sundays


The Garage Bar & Sandwiches is a neighborhood hangout spot featuring bar fare — like sandwiches and giant preztzels — beer galore, TVs and a rooftop deck.

River North/Gold Coast

Celeste Chicago, 111 W. Hubbard St. Credit: Provided


111 W. Hubbard St.


7 p.m.-4 a.m. Wednesday-Friday, 7 p.m.-5 a.m. Saturdays


This multi-level River North establishment offers a pub serving up American cuisine and a Deco Room with craft cocktails. Head on up to the fourth floor for Celeste’s rooftop garden, complete with Victorian decor, tropical greenery and a retractable glass rooftop for year-round enjoyment.

Joy District

112 W. Hubbard St.


4 p.m.-2 a.m. Monday-Friday, 11 a.m.-3 a.m. Saturdays, 11 a.m.-midnight Sundays


Across from Celeste is Joy District, another multi-level drinking and dining establishment. It features a first-floor sports parlor and a second-floor club and rooftop bar where visitors can dance the night away while looking out at the city’s skyline.


1112 N. State St.


5-11 p.m. Tuesday-Saturday


Share baos and buns in the heart of Gold Coast at Pandan, a botanical 18th floor bar at Viceroy Chicago with a “cocktail menu is as vast as the skyline itself.” The rooftop was previously called Devereaux.


118 W. Grand Ave.


5-9 p.m. Monday-Thursday, 5-10 p.m. Fridays, 11 a.m.-2 p.m. and 5-10 p.m. Saturdays, 11 a.m.-2 p.m. and 5-9 p.m. Sundays


Tanta brings a taste of Peru to Chicago with empanadas, cebiches and a variety of grilled seafood dishes and more, served on the restaurant’s indoor dining room and second-floor rooftop. Enjoy a meal alongside with a cocktail, including Peru’s national cocktail, Pisco Sour.

South Loop

Plymouth Restaurant & Bar rebranded to Pancho’s Rooftop Cantina, 327 S. Plymouth Court. Credit: Provided

Pancho’s Rooftop & Cantina

327 S. Plymouth Court


4 p.m.-midnight Tuesday-Wednesday, 3 p.m.-midnight Thursday-Friday, 11 a.m.-midnight Saturday-Sunday


Formerly Plymouth Restaurant & Bar, this rebranded rooftop opened in the spring. Diners can enjoy nachos, burgers, tacos, salads, asada and barbacoa fries, margaritas and more.


520 W. Taylor St.


10-1 a.m. daily


Beloved Chicagoland hot dog chain Portillo’s has an open-air rooftop patio where diners can enjoy Chicago-style wieners and a classic shake.

Reggies Rooftop Deck

2109 S. State St.


11-2 a.m. Monday-Friday, 11-3 a.m. Saturday


Neighborhood bar and music joint Reggies also has a “Trainwreck Rooftop Deck” with eight flat-screen TVs, a pool table, pro basketball pop-a-shot, bags games and more. Take a seat, sip some booze and enjoy the South Side club’s classic menu items.

West Loop/Fulton Market


302 N. Green St.


4-10 p.m. Monday-Thursday, 4-11 p.m. Fridays, 10 a.m.-2:30 p.m. and 3-11 p.m. Saturdays, 10 a.m.-2:30 p.m. and 3-10 p.m. Sundays


Aba serves up Israeli, Lebanese, Turkish and Greek cuisine and rare Mediterranean-inspired wines and spirits. Visitors can sit indoors for a traditional dining experience or take advantage of the eatery’s year-round rooftop patio, which becomes fully enclosed and heated during the winter.


200 N. Green St.


11 a.m.-3:30 p.m. and 4-10 p.m. Monday-Thursday, 11 a.m.-3:30 p.m. and 4-11 p.m. Fridays, 11 a.m.-11 p.m. Saturdays, 11 a.m.-10 p.m. Sundays


Enjoy panoramic views of the city while sipping on cocktails and wines and tasting shareable plates of Peruvian cuisine, meant to be enjoyed family-style. With indoor and outdoor space atop The Hoxton Chicago Hotel, you can visit the rooftop year-round.

La Josie, 740 W. Randolph St. Credit: Provided

La Josie

740 W. Randolph St.


4-11 p.m. Monday-Wednesday, noon-11 p.m. Thursdays, noon-4 p.m. Fridays, 11 a.m.-midnight Saturday-Sunday


Amid Chicago’s cityscape in West Loop sits La Josie, a modern and casual Mexican restaurant and agave bar with an open-air rooftop. Visitors can dine on tacos and ceviche, sip on cocktails and more while string lights twinkle overhead.

Parlor Pizza Bar

108 N. Green St.


11:30 a.m.-11:30 p.m. Monday-Wednesday, 11:30 a.m.-12:30 a.m. Thursday-Friday, 10:30 a.m.-12:30 a.m. Saturdays, 10:30 a.m.-11:30 p.m. Sundays


Parlor’s first location in the heart of West Loop is known for its unique ‘za and craft beer and cocktails. Diners can enjoy a casual meal on its open-air patio and rooftop spaces. Parlor also has a patio in Wicker Park and an indoor restaurant in River North.


932 W. Randolph St.


4 p.m.-midnight Monday-Thursday, noon-2 a.m. Fridays, 11-2 a.m. Saturdays, noon-midnight Sundays


After playing indoor mini golf, you can head to Puttery’s patio for drinks, pizza and upscale bites like potato flautas and charcuterie boards. This indoor-outdoor space offers lounge spaces, bar tops and communal tables so you can chill after tee time.

Rooftop At Nobu Hotel

155 N. Peoria St.


Find dining room, bar lounge and takeout hours here


Nobu’s global luxury hotel in West Loop features an 11th-floor outdoor terrace distinguished by its minimalistic, Japanese-inspired decor and menu items. Sip on booze and snack on wagyu dumplings or nigiri while looking out at the city’s skyline.


311 N. Morgan St.


5 p.m.-midnight Tuesday-Thursdays, 5 p.m.-1 a.m. Friday-Saturday


This Mexican nights-inspired bar on the seventh floor of The Emily Hotel is a moody and intimate indoor-outdoor venue. You can try its handcrafted cocktails, like a Blackberry Mojito or Oaxaca Old Fashioned, plus casual fare like tacos, quesadillas and chips and salsa.

Soho House Chicago

113-125 N. Green St.


7 a.m.-midnight Sunday-Tuesday, 7-1 a.m. Wednesdays, 7-2 a.m. Thursday-Saturday


Soho House Chicago spans five floors and 108,000 square feet. Alongside a chic rooftop for drinks and lounging, there’s a rooftop pool, indoor screening room, gym, spa and music and arts programs.

Tetto Chicago

406 N. Sangamon St.


4-11 p.m. Wednesday-Thursday, 4 p.m.-midnight Friday-Saturday, 4-11 p.m. Sundays


Tetto Chicago opened one year ago and sits atop the building that houses taco spot Tabu. Alongside city views, it serves up pizza slices and pies from Professor Pizza and a lineup of summer cocktails.

Texan Taco Bar

942 W. Randolph St.


11:30 a.m.-11:15 p.m. Monday-Wednesday, 11:30 a.m.-12:30 a.m. Thursdays, 11:30 a.m.-2 a.m. Fridays, 10:30 a.m.-3 a.m. Saturdays, 10:30 a.m.-11:15 p.m. Sundays


In the heart of West Loop overlooking Randolph Street is Texan Taco Bar. It comes from the owners of Parlor Pizza, and it’s known for its fresh-squeezed margaritas, hardshell tacos and more Tex-Mex favorites.

Tony’s Rooftop Bar

916 W. Fulton Market


8 a.m.-10 p.m. Monday-Friday, 9 a.m.-10 p.m. Saturdays, 9 a.m.-9 p.m. Sundays


Time Out Market’s rooftop bar, named after the magazine’s late founder, Tony Elliot, features a cozy, all-season venue decorated in vintage Time Out London covers and twinkling lights. Catch views of the Willis Tower and other architectural gems while sipping on a curated selection of wines, beers and signature cocktails.

Homestead On The Roof, 1924 W. Chicago Ave. Credit: Provided

West Town

Homestead On The Roof

1924 W. Chicago Ave.


5-9 p.m. Wednesdays and Sundays, 5-11 p.m. Thursday-Saturday


Touting itself Chicago’s “secret garden,” Homestead On The Roof is a cozy rooftop above Roots Handmade Pizza. Diners can enjoy a seasonal pop-up menu while surrounded by flowers, vertical hanging gardens, string lights and a decorative outdoor fireplace.

Twisted Spoke

501 N. Ogden Ave.


11 a.m.-2 a.m. Monday-Friday, 9 a.m.-3 a.m. Saturdays, 9 a.m.-2 a.m. Sundays


For 28 years, Twisted Spoke has been West Town’s “burger, booze and biker bar.” Enjoy fried fish tacos, jalapeno poppers and more late-night bar foods with a margarita, mint julep or two-for-one whiskey special. There’s also refreshing salads, like the popular Anarchy Greens with seared avocado, pear, garbanzos, dried black olives, blue cheese and more.

Wicker Park/Bucktown

The Robey’s Cabana Club, 2018 W. North Ave., features a rooftop pool. Credit: Provided

Cabana Club

2018 W. North Ave.


11 a.m.-11 p.m. Sunday-Thursday, 11 a.m.-midnight Friday-Saturday


You’ll find Cabana Club just a few floors down from the Up Room. The Cabana Club, on The Robey’s sixth floor, is an indoor-outdoor cocktail bar with 180-degree views of the Chicago skyline. You can also enjoy frozen cocktails and maybe even take a dip in the pool.

Chop Shop

2033 W. North Ave.


5-9 p.m. Monday-Wednesday, 11 a.m.-4 p.m. and 5-9 p.m. Thursday-Saturday, 11 a.m.-4 p.m. Sundays


Housed in a 100-year-old former auto body shop, Chop Shop is a butcher, deli, restaurant, bar and music venue all in one. It also has an open-air rooftop patio where guests can enjoy a meal, drinks or summer concert.


1840 W. North Ave.


5-10 p.m. Monday-Thursday, 4:30-11 p.m. Fridays, 10 a.m.-2 p.m and 4:30-11 p.m. Saturdays, 10 a.m.-9 p.m. Sundays


New American restaurant Etta is all about rustic, wood-fired cooking, serving up pizzas, housemade pastas and salads which patrons can enjoy on a rooftop terrace.

At seven stories high, Kennedy Rooftop, 1551 W. North Ave., offers an all-encompassing view of Chicago’s skyline. Credit: Leen Yassine/Block Club Chicago

Kennedy Rooftop

1551 W. North Ave.


4-10 p.m. Monday-Thursday, 4-11 p.m. Friday-Saturday, 11 a.m.-5 p.m. Sundays


Atop the seventh floor of the Hyatt Place Wicker Park, you’ll find the Kennedy Rooftop, an open-air lounge complete with fire pits, oversized Jenga sets and panoramic skyline views. Enjoy craft cocktails, shareable mezze platters and flatbreads and dishes like harissa chicken kabobs and mahi mahi tacos.

Royal Palms Shuffleboard Club

1750 N. Milwaukee Ave.


Find indoor and outdoor hours here


Tropical drinks, rotating food trucks, board games, DJs and 11 shuffleboard courts are just some of the things you’ll find at this May-September shuffleboard club. Walk-ins are always welcome to join in the shuffle boarding or to simply lounge on the roof deck with a pina colada in hand.

Taxim Chicago

1558 N. Milwaukee Ave.


5:30-10 p.m. Monday-Thursday, 5:30-11 p.m. Friday, 5-11 p.m. Saturdays, 5-9 p.m. Sundays


Greek cuisine and wine abound at Taxim Chicago, a Byzantine-inspired venue that regularly hosts live Greek music, dancing and food events. Enjoy a meal on the rooftop terrace, which is now open for dinner service.

The Up Room

2018 W. North Ave.


5 p.m.-midnight Sunday-Thursday, 5 p.m.-1 a.m. Friday-Saturday


Thirteen floors above the Wicker Park’s bustling Milwaukee Avenue, you can sit atop this Robey Hotel cocktail bar, lounge around and sip booze while looking out at the breathtaking cityscape.

Whiskey Business

1367 N. Milwaukee Ave.


2-10:30 p.m. Wednesday-Thursday, 2-11:15 p.m. Fridays, 10 a.m.-11:15 p.m. Saturdays, 10 a.m.-10:30 p.m. Sundays


In the heart of Wicker Park, Whiskey Business mixes ’80s and ’90s nostalgia in its bi-level restaurant and bar. It’s rooftop hosts pop-up concepts.


Alma’s rooftop, 3630 N. Clark St., in Wrigleyville. Credit: Leen Yassine/Block Club Chicago


3630 N. Clark St.


3-11 p.m. Sunday-Wednesday, 3 p.m.-midnight Thursday, 3 p.m.-1 a.m. Friday-Saturday


Hidden in plain sight on Wrigleyville’s Hotel Zachary, Alma is a second-floor rooftop bar and lounge offering Mediterranean-inspired bites. The neighborhood social hub offers indoor and outdoor seating, a DJ booth and views of Wrigley Field and Gallagher Way.

Old Crow Smokehouse

3506 N. Clark St.


3 p.m.-midnight Tuesday-Wednesday, 10-1 a.m. Thursday, 5 p.m.-1 a.m. Friday, 11-2 a.m. Saturdays, 11 a.m.-midnight Sundays


For country music, whiskey, Southern brunch and game-day celebrations in the heart of Wrigleyville, Old Crow Smokehouse is the spot. The indoor-outdoor restaurant and bar features a second-floor rooftop to bask in the sunlight.

The Dugout

950 W. Addison St.


5 p.m.-2 a.m. Mondays, 2 p.m.-2 a.m. Tuesday-Wednesday, 5 p.m.-2 a.m. Thursday-Friday, 5 p.m.-3 a.m. Saturdays, 5 p.m.-2 a.m. Sundays


Laidback spots bar The Dugout has a rooftop patio that offers views of the Chicago skyline and Wrigley Field, which is just steps away.

Wrigley Rooftops

3609 N. Sheffield Ave.


Select dates and times with reservations


Catch a Chicago Cubs game from rooftop bleachers. You can make single or group reservations, and food and drinks are included. Game tickets are required to get in.

Wrigley View Rooftop, 1050 W. Waveland Ave., overlooking Wrigley Field. Credit: Provided

Wrigley View Rooftops

1050 W. Waveland Ave.


Select dates and times with reservations


Multi-level facility Wrigley View Rooftops is another option for Cubs fans looking for a nearby rooftop to watch the game. Game tickets are required to get in.

Vines On Clark

3554 N. Clark St.


10:30 a.m.-midnight Thursdays, 11-1 a.m. Saturdays, 11 a.m.-midnight Sundays


Steps away from Wrigley Field is Vines On Clark, a popular bar and neighborhood hangout. Enjoy drinks and comfort food in an indoor-outdoor venue, which includes a patio and second-floor rooftop.

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heliophile-oxon:piningforthefjords:goddessactuality:Pierre Fouché. 1994.77 or Le...

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Pierre Fouché. 1994.77 or Lebenslänglichen Explosionsglück, 2020.

Rayon chords from a World War II parachute.

PBY Blister Gunner, Rescue at Rabaul, 1944, photo by Horace Bristol

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At least show us the bison!


The best update.

wholesome and true - do not mess with the wildlife

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If you refuse to do the bare minimum to reduce the effects of genocide, I don’t really trust your…

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By existing as a citizen in and paying taxes to the imperial core, we automatically hold complicity in imperialist oppression because we are literally footing the bill for it. That is just the basic nature of being born to privilege in systems of oppression in general. We can be disadvantaged and marginalized in every single other consideration and we still have to understand and cope with this, and ensure we leverage it as effectively as possible.

Voting abstinence/sabotage does not absolve us of our responsibility to do everything in our power to lessen harm, but it DOES show that when our personal morals aren’t satisfied, we retreat into (imperialist, this time) privilege to ‘wash our hands’ of the situation and declare it’s not our fault and it’s not our problem.

If you refuse to do the bare minimum to reduce the effects of genocide, I don’t really trust your commitment to ending it.

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The only thing university administrators had to do was NOTHING.


I am not on campus this semester. I’m on sabbatical, sitting in coffeehouses, writing blog posts and a book.

But if I were on campus this semester, yesterday I would have seen the quad across the street filled with tents yesterday. And then I would have seen the police arrive, to break up the encampment. Not the campus cops either — the real ones.

Those are my students occupying the tents. I don’t mean that figuratively. Among the students who organized the protest action on campus yesterday are almost certainly people who have taken my strategic political communication class. They’ve shown up to my office hours. They did the reading. (FWIW, several of them are jewish.)

One book that I have my students read every semester is E.E. Schattschneider’s 1960 classic, The Semi-Sovereign People. The book is a tight 180 pages. It weighs only 7.1 ounces. I mention its weight because, if I were on any college campus right now, I would be mighty tempted to smack a few administrators in the face with it. Doing so would leave an impression without leaving a mark.

Schattschneider tells us that contentious politics can be best understand through a lens of conflict expansion. Those in power will (and, strategically, should) try to maintain and contain the scope of a conflict. Those arrayed against them will (and should) attempt to expand the scope of the conflict. If you want to understand an episode of contentious politics, don’t evaluate the substance of the arguments as though you are judging an intercollegiate debate. Instead, watch the crowd.

I don’t personally know Columbia University’s President, Minouche Shafik. But I am pretty confident that, unlike my students, she has not read her Schattschneider.

If you had asked me on April 17th what I thought of the Columbia University encampment, I would’ve shrugged my shoulders before apologetically explaining why it didn’t seem like an especially powerful tactic. Around 100 Columbia University students had set up a tent city on the campus quad. They were standing in solidarity with the residents of Gaza, while making demands of the campus administration.

This is a radical tactic, but it is not a novel tactic. It breaks campus rules while demonstrating commitment and solidarity among the participants. But it is also a radical tactic that is relatively easy to defuse or ignore. There is less than month until finals and the end of the semester. The students aren’t preventing the university from operating. They are making some noise and making a scene. Once the semester ends, the campus shuts down, as does the encampment.

The way that administrators normally respond to a tactic like this is to just wait it out. Have campus security keep an eye on them to make sure things don’t get out of hand. Make vague statements to the campus paper. Schedule some meetings. Maybe declare that you’ll form a committee to look into things further.

Traditionally, the weakness of this tactic is that it does little to expand the conflict. Students are outraged. They have demands. But they don’t have numbers or time on their side. Even when the majority of their peers agree with them, so long as the administration slow-walks the response, it will remain a conflict between the most-committed student activists and a slow-moving bureaucracy.

All the administration has to do is nothing. University administrators are great at doing nothing.

But that’s not how it looked to President Shafik. Because she wasn’t responding to the students.

She was responding to the former Presidents of Harvard and Penn.

Here’s the basic timeline of events.

  • Five months ago, the Presidents of Harvard, Penn, and MIT testified before a House committee. This was a trap. It was not subtle. Everyone knew it was a trap.

  • Instead of prepping for the testimony by talking to a comms professional, they prepped by talking to a lawyer. (Don’t do that. Don’t treat televised spectacle like a deposition. It will go badly for you in all the very predictable ways.)

  • Having screwed that up, outraged conservative alumni were able to force Penn’s President to resign. That was a win for them. They tried to force Harvard’s President to resign. That didn’t work, so they ginned up some more faux scandals until they got their way. Double-win.

  • Fast-forward to this month. Columbia’s President is asked to testify before the House committee as well.

  • She decides to do the opposite of those other Ivy League Presidents. That, apparently, is her entire comms strategy. Just agree with everything the hostile Republicans say, and hope they applaud you at the end.

  • But they aren’t asking these questions in good faith. They are strategic actors, pursuing another win. (Again, this isn’t exactly subtle.)

  • Having given them every answer they asked for, she then went back to campus and clamped down on the protest, in order to prove that she really totally meant it, guuuuuuys.

  • They’re calling for her resignation anyway, and turning Columbia into a prop. Of course they are. That’s what they were planning to do anyway. You only win against these Congressional Republicans by refusing to play their game.

  • But in the meantime, she called in the NYPD to clear the encampment. And she tried to shut down the campus radio station. And she barred journalists (IN NEW YORK!) from covering the Columbia protests (DESPITE COLUMBIA JOURNALISM SCHOOL BEING THE PLACE THAT AWARDS THE PULITZERS).

  • And, oh yeah, now that the conflict has expanded, a bunch of protestors unaffiliated with the university, some of whom are rabid antisemites, are showing up and shouting things at students in front of cameras as well. Not great, because this part can potentially escalate in directions that pose an actual safety risk to students. (Unlike the encampment, which wasn’t a risk to anyone. And which you could’ve just ignored if you weren’t shadowboxing the phantom figures of other universities’ former presidents.)

  • So now you’ve launched the biggest crackdown on campus speech since the 1960s. The conflict has now expanded. Every college campus is now going to feature an encampment. And that encampment is both a show of solidarity with people in Gaza and a show of solidarity with students at Columbia. (And Emory. And UT Austin. And probably a dozen other places.)

All you had to do was ignore the fuckin’ encampment for a month. Maybe make a bland statement. Have campus security issue a citation or two. Declare that a committee is going to look into things.

Saul Alinsky writes that “the action is in the reaction.” The campus encampments don’t work if you don’t react to them. And not reacting to student speech on campus is usually one of the things that university administrators do best.

Instead, here we are. Snipers on the roofs of major universities. Encampments springing up everywhere. Actual cops arresting students and faculty. Enough of a spotlight that every university administration is worried that shit might go sideways. Republican politicians gleefully egging it on, crowing about “chaos on campus.” (Because the more this moment resembles 1968 on tv, the better.)

The conflict has expanded. Colleges are passing draconian measures to clamp down on campus protest. Students are responding to those actions, and responding to the police violence. The action is in the OVER-reaction. The semester will end soon, but it now seems more likely that it will form an ellipses instead of an ending.

I’m worried for my students. They are smart and they are brave and they are outraged. They are facing batons and tear gas. This escalation did not have to happen. This escalation will not end well.

I blame Republican legislators. But I also expected them to behave this way. Tom Cotton is exactly how we thought he was. Elise Stefanik’s outrage is scripted, typecast. They have not been subtle about their views or intentions.

I did expect more from University administrators — Shafik especially. All she had to do was act like an average university administrator. Make noncommittal promises, and wait.

Now this is spiraling. And I sit here in this coffeehouse, tapping away at the keyboard. Hoping my students are safe. Hoping I taught them well enough. Wishing that the people who run universities would learn anything at all.

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54 days ago
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Decentralized Systems Aren't

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Below the fold is the text of a talk I gave to Berkeley's Information Systems Seminar exploring the history of attempts to build decentralized systems and why so many of them end up centralized.

As usual, you don't need to take notes. The text of my talk with links to the sources will go up at blog.dshr.org after this seminar.

Why Decentralize?

Tweets by language
This is a map of the location of tweets in Europe, colored by language. It vividly shows the contrast between a centralized society and more decentralized ones. I hope we can agree as to which one we'd prefer to live in.

The platonic ideal of a decentralized system has many advantages over a centralized one performing the same functions:
  1. It can be more resilient to failures and attacks.
  2. It can resist acquisition and the consequent enshittification.
  3. It can scale better.
  4. It has the economic advantage that it is hard to compare the total system cost with the benefits it provides because the cost is diffused across many independent budgets.

Why Not Decentralize?

But history shows that this platonic ideal is unachieveable because systems decentralization isn't binary and systems that aim to be at the decentralized end of the spectrum suffer four major problems:
  1. Their advantages come with significant additional monetary and operational costs.
  2. Their user experience is worse, being more complex, slower and less predictable.
  3. They are in practice only as decentralized as the least decentralized layer in the stack.
  4. They exhibit emergent behaviors that drive centralization.

What Does "Decentralization" Mean?

In Gini Coefficients Of Cryptocurrencies I discussed various ways to measure decentralization. Because decentralization applies at each layer of a system's stack, it is necessary to measure each of the subsystem individually. In 2017's Quantifying Decentralization Srinivasan and Lee identified a set of subsystems for public blockchains, and measured them using their proposed "Nakamoto Coefficient":
The Nakamoto coefficient is the number of units in a subsystem you need to control 51% of that subsystem.
Their table of the contemporary Nakamoto coefficients for Bitcoin and Ethereum makes the case that they were only minimally decentralized.

Blockchains exemplify a more rigorous way to assess decentralization; to ask whether a node can join the network autonomously, or whether it must obtain permission to join. If the system is "permissioned" it cannot be decentralized, it is centralized around the permission-granting authority. Truly decentralized systems must be "permissionless". My title is wrong; the talk is mostly about permissionless systems, not about the permssioned systems that claim to be decentralized but clearly aren't.


IBM Cabling System
The world has been on a decades-long series of experiments trying to build successful decentralized systems marked almost entirely by failure. Forty years ago I played a small part in one of the first of these experiments. I was working at Carnegie-Mellon's Information Technology Center on the Andrew Project, one of three pioneering efforts in campus networking. The others were at Brown and MIT. It was generously funded by IBM, who were covering the campus with the massively over-engineered "IBM Cabling System". They really wanted these wires to carry IBM's Token Ring network supporting IBM's System Network Architecture (SNA). SNA was competing with the telco's X.25 and DARPA's IP stack for the future of networking, and it wasn't clear which would win. But the three campus projects were adamant that their networks would run IP, largely because it was non-proprietary and far less centralized.

Domain Name System

It is true that TCP/IP now dominates the bottom layers of the stack, but the common complaint is that the systems layered on it are excessively centralized. DNS is centralized around the root servers and IANA's (Internet Assigned Numbers Authority) management of top-level DNS domains and the global IP and AS spaces. They are the Internet's permission-granting authority. To scale, they have delegated management of sub-spaces to others, but the fundamental centralization remains. The Web is so centralized around the tech giants that there is an entire decentralized web movement. E-mail is increasingly centralized around a few major providers making life for those like me who run their own e-mail servers more and more difficult.

The basis of TCP/IP is the end-to-end principle, that to the extent possible network nodes communicate directly with each other, not relying on functions in the infrastructure. So why the need for root servers and IANA? It is because nodes need some way to find each other, and the list of root servers' IP addresses provides a key into the hierarchical structure of DNS.

This illustrates the important point that a system is only as decentralized as the least decentralized layer in its stack.


Fifteen years on from CMU when Vicky Reich and I started the LOCKSS program we needed a highly resilient system to preserve library materials, so the advantages of decentralization loomed large. In particular, we realized that:
  • A centralized system would provide an attractive target for litigation by the publisher oligopoly.
  • The paper library system already formed a decentralized, permissionless network.
Our idea was to build a permissionless peer-to-peer system in which libraries would hold copies of their subscription content and model the paper inter-library loan and copy system to repair any loss or damage to them. To detect loss or damage the nodes would vote on the hash of the content. We needed to defend against a "Sybil attack", in which a bad guy wishing to change some content would create enough nodes under his control to win the votes on it. Our initial attempts at designing a protocol were flawed, but we eventually won a "Best Paper" award at the 2003 SOSP conference for a protocol that used proof-of-work (PoW) as a way of making running a node expensive enough to deter Sybil attacks. An honest library need only run one node, the bad guy had to run more than the total of the honest libraries, so would pay many times the per-library cost.

Why LOCKSS Centralized

  • Software monoculture
  • Centralized development
  • Permissioning ensures funding
  • Big publishers hated decentralization
Although the LOCKSS technology was designed and implemented to be permissionless, there were a number of reasons why it turned out much less decentralized than we hoped:
  • Although we always paid a lot of attention to the security of LOCKSS boxes, we understood that a software monoculture was vulnerable to software supply chain attacks. So we designed a very simple protocol hoping that there would be multiple implementations. But it turned out that the things that a LOCKSS box needed to do other than handling the protocol were quite complex, so despite our best efforts we ended up with a software monoculture.
  • We hoped that by using the BSD open-source license we would create a diverse community of developers, but we over-estimated the expertise and the resources of the library community, so Stanford provided the overwhelming majority of the programming effort.
  • The program got started with small grants from Michael Lesk at NSF, then subsequently major grants from the NSF, Sun Microsystems and Don Waters at the Mellon Foundation. But Don was clear that grant funding could not provide the long-term sustainability needed for digital preservation. So he provided a matching grant to fund the transition to being funded by the system's users. This also transitioned the system to being permissioned, as a way to ensure the users paid.
  • Although many small and open-access publishers were happy to allow LOCKSS to preserve their content, the oligopoly publishers never were. Eventually they funded a completely closed network of a dozen huge systems at major libraries around the world called CLOCKSS. This is merely the biggest of a number of closed, private LOCKSS networks that were established to serve specific genres of content, such as government documents.

Gossip Protocols

If LOCKSS was to be permissionless there could be no equivalent of DNS, so how did a new node find other nodes to vote with?

A gossip protocol or epidemic protocol is a procedure or process of computer peer-to-peer communication that is based on the way epidemics spread. Some distributed systems use peer-to-peer gossip to ensure that data is disseminated to all members of a group. Some ad-hoc networks have no central registry and the only way to spread common data is to rely on each member to pass it along to their neighbors.

Suppose you have a decentralized network with thousands of nodes that can join and leave whenever they want, and you want to send a message to all the current nodes. This might be because they are maintaining a shared state, or to ask a question that a subset might be able to answer. You don't want to enumerate the nodes, because it would be costly in time and network traffic, and because the answer might be out-of-date by the time you got it. And even if you did sending messages individually to the thousands of nodes would be expensive. This is what IP multicast was for, but it doesn't work well in practice. So you build multicast on top of IP using a Gossip protocol.

Each node knows a few other nodes. The first time it receives a message it forwards it to them, along with the names of some of the nodes it knows. As the alternate name of "epidemic protocol" suggests, this is a remarkably effective mechanism. All that a new node needs in order to join is for the network to publish a few "bootstrap nodes", similar to the way an Internet node accesses DNS by having the set of root servers wired in. But this bootstrap mechanism is inevitably centralized.

The LOCKSS nodes used a gossip protocol to communicate, so in theory all a library needed to join in was to know another library running a node. In the world of academic libraries this didn't seem like a problem. It turned out that the bootstrap node all the libraries knew was Stanford, the place they got the software and the support. So just like DNS, the root identity was effectively wired-in.


The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'll generate the longest chain and outpace attackers.
Satoshi Nakamoto

Fast forward another ten years and Satoshi Nakamoto published Bitcoin: A Peer-to-Peer Electronic Cash System, a ledger implemented as a chain of blocks containing transactions. Like LOCKSS, the system needed a Sybil-proof way to achieve consensus, in his case on the set of transactions in the next block to be added to the chain. Unlike LOCKSS, where nodes voted in single-phase elections, Nakamoto implemented a three-phase selection mechanism:
  1. One node is selected from the network using Proof-of-Work. It is the first node to guess a nonce that made the hash of the block have the required number of leading zeros.
  2. The selected node proposes the content of the next block via the gossip network.
  3. The "longest chain rule", Nakamoto's most important contribution, ensures that the network achieves consensus on the block proposed by the selected node.

Increasing Returns to Scale

More than a decade earlier, W. Brian Arthur had published Increasing Returns and Path Dependence in the Economy explaining how the very strong economies of scale inherent to technology markets led to them being monopolized. Consider a new market opened up by a technological development. Several startups enter, for random reasons one gets bigger then the others, economies of scale make it more profitable and network effects make it more attractive to new customers, so this feedback loop drives it to out-compete the others.

The application to the Bitcoin network starts with this observation. The whole point of the Bitcoin protocol is to make running a miner, a node in the network, costly. The security of the system depends upon making an attack more costly to mount than it would gain. Miners need to defray the costs the system imposes in terms of power, hardware, bandwidth, staff and so on. Thus the protocol rewards miners with newly minted Bitcoin for winning the race for the next block.

Bitcoin Economics

Nakamoto's vision of the network was of many nodes of roughly equal power,"one CPU one vote". This has two scaling problems:
  • The target block time is 10 minutes, so in a network of 600 equal nodes the average time between rewards is 100 hours, or about 4 days. But in a network of 600,000 equal nodes it is about 4,000 days or about 11 years. In such a network the average node will never gain a reward before it is obsolete.
  • Moore's law means that over timescales of years the nodes are not equal, even if they are all CPUs. But shortly after Bitcoin launched, miners figured out that GPUs were much better mining rigs than CPUs, and later that mining ASICs were even better. Thus the miner's investment in hardware has only a short time to return a profit.
Mining Pools 02/27/23
The result was the formation of mining pools, allowing miners to contribute their power to a single huge node and trade their small chance of an infrequent large reward for a frequent flow of a small share of the node's rewards. But economies of scale applied even below the level of pools. A miner who could fill a warehouse with mining rigs or who was able to steal electricity would have much lower costs than a smaller miner. Thus they would not merely get more of the pool's block rewards, but they would keep more of them as profit. The success of this idea led to GHash.io's single node controlling the Bitcoin network with over 51% of the mining power. Most of it was from warehouses full of mining rigs.

The block rewards inflate the currency, currently by about $100M/day. This plus fees that can reach $23M/day, is the cost to run a system that currently processes 400K transactions/day, or over $250 per transaction plus up to $57 per transaction in fees. Lets talk about the excess costs of decentralization!

Like most permissionless networks, Bitcoin nodes communicate using a gossip protocol. So just like LOCKSS boxes, they need to know one or more bootstrap nodes in order to join the network, just like DNS and LOCKSS.
In Bitcoin Core, the canonical Bitcoin implementation, these bootstrap nodes are hard-coded as trusted DNS servers maintained by the core developers.
Haseeb Qureshi, Bitcoin's P2P Network
There are also fall-back nodes in case of DNS failure encoded in chainparamsseeds.h:
 * List of fixed seed nodes for the bitcoin network
 * AUTOGENERATED by contrib/seeds/generate-seeds.py
 * Each line contains a BIP155 serialized (networkID, addr, port) tuple.

Economies of Scale in Peer-to-Peer Networks

Fast forward another five years. Vicky Reich and I were driving North in my RX-7 for a long weekend at the Mendocino Hotel. On US101 before the driving got interesting on CA128 I was thinking about the recent period during which the GHash.io mining pool controlled 51% of Bitcoin's mining power.

I suddenly realized that this centralization wasn't something about Bitcoin, or LOCKSS for that matter. It was an inevitable result of economic forces generic to all peer-to-peer systems. So I spent much of the weekend sitting in one of the hotel's luxurious houses writing Economies of Scale in Peer-to-Peer Networks.

My insight was that the need to make an attack expensive wasn't something about Bitcoin, any permissionless peer-to-peer network would have the same need. In each case the lack of a root of trust meant that security was linear in cost, not exponential as with, for example, systems using encryption based upon a certificate authority. Thus any successful decentralized peer-to-peer network would need to reimburse nodes for the costs they incurred. How can the nodes' costs be reimbursed?:
There is no central authority capable of collecting funds from users and distributing them to the miners in proportion to these efforts. Thus miners' reimbursement must be generated organically by the blockchain itself; a permissionless blockchain needs a cryptocurrency to be secure.
And thus any successful permissionless network would be subject to the centralizing force of economies of scale.


ETH miners 11/2/20
There have been many attempts to create alternatives to Bitcoin, but of the current total "market cap" of around $2.5T Bitcoin and Ethereum represent $1.75T or 70%. The top 10 "decentralized" coins represent $1.92T, or 77%, so you can see that the coin market is dominated by just two coins. Adding in the top 5 coins that don't even claim to be decentralized gets you to 87% of the total "market cap".

The fact that the coins ranked 3, 6 and 7 by "market cap" don't even claim to be decentralized shows that decentralization is irrelevant to cryptocurrency users. Numbers 3 and 7 are stablecoins with a combined "market cap" of $134B. The largest stablecoin that claims to be decentralized is DAI, ranked at 24 with a "market cap" of $5B. Launching a new currency by claiming better, more decentralized technology than Bitcoin or Ethereum is pointless, as examples such as Chia, now ranked #182, demonstrate. Users care about liquidity, not about technology.

The holders of coins show a similar concentration, the Gini Coefficients Of Cryptocurrencies are extreme.

Ethereum's Merge

ETH Stakes 05/22/23
Ethereum made a praiseworthy effort to reduce their environmental impact by switching from Proof-of-Work to Proof-of-Stake and, in an impressive feat of software engineering, managed a smooth transition. The transition to Proof-of-Stake did in fact greatly reduce the Ethereum network's power consumption. Some fraction of the previous mining power was redirected to mine other Proof-of-Work coins, so the effect on the power consumption of cryptocurrencies as a whole was less significant. But it didn't reduce centralization, as the contrast between the before and after pie-charts shows.

Ethereum Validators

Time in proof-of-stake Ethereum is divided into slots (12 seconds) and epochs (32 slots). One validator is randomly selected to be a block proposer in every slot. This validator is responsible for creating a new block and sending it out to other nodes on the network. Also in every slot, a committee of validators is randomly chosen, whose votes are used to determine the validity of the block being proposed. Dividing the validator set up into committees is important for keeping the network load manageable. Committees divide up the validator set so that every active validator attests in every epoch, but not in every slot.
Ethereum's consensus mechanism is vastly more complex than Bitcoin's, but it shares the same three-phase structure. In essence, this is how it works. To take part, a node must stake, or escrow, more than a minimum amount of the cryptocurrency,then:
  1. A "smart contract" uses a pseudo-random algorithm to select one node and a "committee" of other nodes with probabilities based on the nodes' stakes.
  2. The one node proposes the content of the next block.
  3. The "committee" of other validator nodes vote to approve the block, leading to consensus.
Just as Bitcoin and LOCKSS share Proof-of-Work, Ethereum's Proof-of-Stake and LOCKSS share another technique, voting by a random subset of the electorate. In LOCKSS the goal of this randomization was not just "keeping the network load manageable", but also making life hard for the bad guy. To avoid detection, the bad guy needed to vote only in polls where he controlled a large majority of the random subset of the nodes. This was something it was hard for him to know. I'm not clear whether the same thing applies to Ethereum.

Like Bitcoin, the nodes taking part in consensus gain a block reward currently running at $2.75M/day and fees running about $26M/day. This is the cost to run a distributed computer 1/5000 as powerful as a Raspberry Pi.

Validator Centralization

The prospect of a US approval of Ether exchange-traded funds threatens to exacerbate the Ethereum ecosystem’s concentration problem by keeping staked tokens in the hands of a few providers, S&P Global warns.
Coinbase Global Inc. is already the second-largest validator ... controlling about 14% of staked Ether. The top provider, Lido, controls 31.7% of the staked tokens,
US institutions issuing Ether-staking ETFs are more likely to pick an institutional digital asset custodian, such as Coinbase, while side-stepping decentralized protocols such as Lido. That represents a growing concentration risk if Coinbase takes a significant share of staked ether, the analysts wrote.

Coinbase is already a staking provider for three of the four largest ether-staking ETFs outside the US, they wrote. For the recently approved Bitcoin ETF, Coinbase was the most popular choice of crypto custodian by issuers. The company safekeeps about 90% of the roughly $37 billion in Bitcoin ETF assets, chief executive officer Brian Armstrong said
Yueqi Yang, Ether ETF Applications Spur S&P Warning on Concentration Risks
A system in which those with lots of money make lots more money but those with a little money pay those with a lot, and which has large economies of scale, might be expected to suffer centralization. As the pie-chart shows, this is what happened. In particular, exchanges hold large amounts of Ethereum on behalf of their customers, and they naturally stake it to earn income. The top two validators, the Lido pool and the Coinbase exchange, have 46.1% of the stake, and the top five have 56.7%.

Producer Centralization

Producers 03/18/24
The concentration is worse for block producers. The chart shows the top producer is generating 47.4% of the blocks and gaining 56.6% of the rewards.

Olga Kharif and Isabelle Lee report that these concentrations are a major focus of the SEC's consideration of Ethereum spot ETFs:
In its solicitations for public comments on the proposed spot Ether ETFs, the SEC asked, “Are there particular features related to ether and its ecosystem, including its proof of stake consensus mechanism and concentration of control or influence by a few individuals or entities, that raise unique concerns about ether’s susceptibility to fraud and manipulation?”

Software Centralization

There is an even bigger problem for Ethereum. The software that validators run is close to a monoculture. Two of the minor players have recently suffered bugs that took them off-line, as Sam Kessler reports in Bug That Took Down 8% of Ethereum's Validators Sparks Worries About Even Bigger Outage:
A bug in Ethereum's Nethermind client software – used by validators of the blockchain to interact with the network – knocked out a chunk of the chain's key operators on Sunday.
Nethermind powers around 8% of the validators that operate Ethereum, and this weekend's bug was critical enough to pull those validators offline. ... the Nethermind incident followed a similar outage earlier in January that impacted Besu, the client software behind around 5% of Ethereum's validators.
Around 85% of Ethereum's validators are currently powered by Geth, and the recent outages to smaller execution clients have renewed concerns that Geth's dominant market position could pose grave consequences if there were ever issues with its programming.
Cygaar cited data from the website execution-diversity.info noting that popular crypto exchanges like Coinbase, Binance and Kraken all rely on Geth to run their staking services. "Users who are staked in protocols that run Geth would lose their ETH" in the event of a critical issue," Cygaar wrote.
The fundamental problem is that most layers in the software stack are highly concentrated, starting with the three operating systems. Network effects and economies of sclae apply at every layer. Remember "no-one ever gets fired for buying IBM"? At the Ethereum layer, it is "no-one ever gets fired using Geth" because, if there was ever a big problem with Geth, the blame would be so widely shared.

The Decentralized Web

One mystery was why venture capitalists like Andreesen Horwitz, normally so insistent on establishing wildly profitable monopolies, were so keen on the idea of a Web 3 implemented as "decentralized apps" (dApps) running on blockchains like Ethereum. Moxie Marlinspike revealed the reason:
companies have emerged that sell API access to an ethereum node they run as a service, along with providing analytics, enhanced APIs they’ve built on top of the default ethereum APIs, and access to historical transactions. Which sounds… familiar. At this point, there are basically two companies. Almost all dApps use either Infura or Alchemy in order to interact with the blockchain. In fact, even when you connect a wallet like MetaMask to a dApp, and the dApp interacts with the blockchain via your wallet, MetaMask is just making calls to Infura!
Providing a viable user experience when interacting with blockchains is a market with economies of scale and network effects, so it has centralized.

It Isn't About The Technology

What is the centralization that decentralized Web advocates are reacting against? Clearly, it is the domination of the Web by the FANG (Facebook, Amazon, Netflix, Google) and a few other large companies such as the cable oligopoly.

These companies came to dominate the Web for economic not technological reasons. The Web, like other technology markets, has very large increasing returns to scale (network effects, duh!). These companies build centralized systems using technology that isn't inherently centralized but which has increasing returns to scale. It is the increasing returns to scale that drive the centralization.

The four FANG companies last year had a combined free cash flow of $159.7B. I know of no decentralized Web effort that has a viable business model. This isn't surprising, since they are focused on developing technology not a business model. This means they pose no threat to the FANG. Consider that, despite Elon Musk's attempts to make it unusable and the availability of federated alternatives such as Mastodon, Twitter retains the vast bulk of its user base. But as I explained in Competition-proofing, if they ever did pose a threat, in the current state of anti-trust the FANGs would just buy them. In 2018 I wrote in It Isn't About The Technology:
If a decentralized Web doesn't achieve mass participation, nothing has really changed. If it does, someone will have figured out how to leverage antitrust to enable it. And someone will have designed a technical infrastructure that fit with and built on that discovery, not a technical infrastructure designed to scratch the itches of technologists.
I think this is still the situation.


Seven years ago I wrote:
Unless decentralized technologies specifically address the issue of how to avoid increasing returns to scale they will not, of themselves, fix this economic problem. Their increasing returns to scale will drive layering centralized businesses on top of decentralized infrastructure, replicating the problem we face now, just on different infrastructure.
The only way that has worked in practice to avoid increasing returns to scale is not to reimburse nodes for their costs, but to require them to be run as a public service. The example we have of avoiding centralization in this way is Bram Cohen's BitTorrent, it is the exception that proves the rule. The network doesn't reward nodes for hosting content, but many sites find it a convenient way to distribute content. The network doesn't need consensus, thus despite being permissionless it isn't vulnerable to a Sybil attack. Users have to trust that the tracker correctly describes its content, so there are other possible attacks. But if we look at the content layer, it is still centralized. The vast majority of the content is at a few large sites like The Pirate Bay.


In 2022 DARPA funded a large team from the Trail of Bits cybersecurity company to publish a report entitled Are Blockchains Decentralized? which conformed to Betteridge's Law by concluding "No":
Every widely used blockchain has a privileged set of entities that can modify the semantics of the blockchain to potentially change past transactions.
The "privileged set of entities" must at least include the developers and maintainers of the software, because:
The challenge with using a blockchain is that one has to either (a) accept its immutability and trust that its programmers did not introduce a bug, or (b) permit upgradeable contracts or off-chain code that share the same trust issues as a centralized approach.
The gossip network underlying Bitcoin has centralized in two ways. First:
A dense, possibly non-scale-free, subnetwork of Bitcoin nodes appears to be largely responsible for reaching consensus and communicating with miners—the vast majority of nodes do not meaningfully contribute to the health of the network.
And second:
Of all Bitcoin traffic, 60% traverses just three ISPs.
Trail of Bits found remarkable vulnerabilities to internal or external supply chain attacks because:
The Ethereum ecosystem has a significant amount of code reuse: 90% of recently deployed Ethereum smart contracts are at least 56% similar to each other.
The risk isn't confined to individual ecosystems, it is generic to the entire cryptosphere because, as the chart shows, the code reuse spans across blockchains to such an extent that Ethereum's Geth shares 90% of its code with Bitcoin Core.

Decentralized Finance

I mentioned Moxie Marlinspike's My first impressions of web3 showing that dApps all used Infura or Alchemy. Many of them implement "decentralized finance" (DeFi), and much research shows this layer has centralized. Prof. Hilary Allen's DeFi: Shadow Banking 2.0? concludes:
TL;DR: DeFi is neither decentralized, nor very good finance, so regulators should have no qualms about clamping down on it to protect the stability of our financial system and broader economy.
DeFi risks and the decentralisation illusion by Sirio Aramonte, Wenqian Huang and Andreas Schrimpf of the Bank for International Settlements similarly conclude:
While the main vision of DeFi’s proponents is intermediation without centralised entities, we argue that some form of centralisation is inevitable. As such, there is a “decentralisation illusion”. First and foremost, centralised governance is needed to take strategic and operational decisions. In addition, some features in DeFi, notably the consensus mechanism, favour a concentration of power.
 $MShare %
Uniswap V35510.0
Maker DAO488.7
AAVE V3244.4
Top 4 78.2
Rari Fuse142.5
Rocket Pool142.5
Pancake Swap AMM V3132.4
Compound V2132.4
Morpho Aave V2101.8
Aura Finance81.5
Yearn Finance71.3
Muyao Shen writes in DeFi Is Becoming Less Competitive a Year After FTX’s Collapse Battered Crypto that:
Based on the [Herfindahl-Hirschman Index], the most competition exists between decentralized finance exchanges, with the top four venues holding about 54% of total market share. Other categories including decentralized derivatives exchanges, DeFi lenders, and liquid staking, are much less competitive. For example, the top four liquid staking projects hold about 90% of total market share in that category,
Based on data on 180 days of revenue of DeFI projects from Shen's article, I compiled this table, showing that the top project, Lido, had 55% of the revenue, the top two had 2/3, and the top four projects had 78%. This is clearly a highly concentrated market, typical of cryptocurrency markets in general.


The alternative to decentralization that is currently popular, especially in social media, is federation. Instead of forming a single system, federation allows many centralized subsystems to interoperate. Examples include BlueSky, Threads and Mastodon. Federation does offer significant advantages, including the opportunity for competition in the policies offered, and the ability for users to migrate to services they find more congenial.

How attractive are these advantages? The first bar chart shows worldwide web traffic to social media sites. Every single one of these sites is centralized, even the barely visible ones like Nextdoor. Note that Meta owns 3 of the top 4, with about 5 times the traffic of Twitter.

The second bar chart shows monthly active users (MAUs) on mobile devices in the US. This one does have two barely visible systems that are intended eventually to be federated, Threads and Bluesky. Despite the opportunity provided by Elon Musk, the federated competitors have had minimal impact:
That leaves Mastodon with a total of 1.8 million monthly active users at present, an increase of 5% month-over-month and 10,000 servers, up 12%
In terms of monthly active users, Twitter claims 528M, Threads claims 130M, Bluesky claims 5.2M and Mastodon claims 1.8M. Note that the only federate-able one with significant market share is owned by the company that owns 3 of the top 4 centralized systems. Facebook claims 3,000M MAU, Instagram claims 2,000M MAU, and WhatsApp claims 2,000 MAU. Thus Threads is about 3% of Facebook alone, so not significant in Meta's overall business. It may be early days yet, but federated social media have a long way to go before they have significant market share.


Radia Perlman's answer to the question of what exactly you get in return for the decentralization provided by the enormous resource cost of blockchain technologies is:
a ledger agreed upon by consensus of thousands of anonymous entities, none of which can be held responsible or be shut down by some malevolent government
This is what the blockchain advocates want you to think, but as Vitalik Buterin, inventor of Ethereum pointed out in The Meaning of Decentralization:
In the case of blockchain protocols, the mathematical and economic reasoning behind the safety of the consensus often relies crucially on the uncoordinated choice model, or the assumption that the game consists of many small actors that make decisions independently. If any one actor gets more than 1/3 of the mining power in a proof of work system, they can gain outsized profits by selfish-mining. However, can we really say that the uncoordinated choice model is realistic when 90% of the Bitcoin network’s mining power is well-coordinated enough to show up together at the same conference?
As we have seen, in practice it just isn't true that "the game consists of many small actors that make decisions independently" or "thousands of anonymous entities". Even if you could prove that there were "thousands of anonymous entities", there would be no way to prove that they were making "decisions independently". One of the advantages of decentralization that Buterin claims is:
it is much harder for participants in decentralized systems to collude to act in ways that benefit them at the expense of other participants, whereas the leaderships of corporations and governments collude in ways that benefit themselves but harm less well-coordinated citizens, customers, employees and the general public all the time.
But this is only the case if in fact "the game consists of many small actors that make decisions independently" and they are "anonymous entities" so that it is hard for the leader of a conspiracy to find conspirators to recruit via off-chain communication. Alas, the last part isn't true for blockchains like Ethereum that support "smart contracts", as Philip Daian et al's On-Chain Vote Buying and the Rise of Dark DAOs shows that "smart contracts" also provide for untraceable on-chain collusion in which the parties are mutually pseudonymous.


If we want the advantages of permissionless, decentralized systems in the real world, we need answers to these questions:
  • What is a viable business model for participation that has decreasing returns to scale?
  • How can Sybil attacks be prevented other than by imposing massive costs?
  • How can collusion between supposedly independent nodes be prevented?
  • What software development and deployment model prevents a monoculture emerging?
  • Does federation provide the upsides of decentralization without the downsides?
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