Skyscrapers in Chicago

How many, and how Chicago compares to New York

About 137 completed buildings in Chicago reach 150 m (492 ft) or more, and 31 of those pass 200 m. The threshold is what makes the number move. Drop it to roughly 100 m, where many lists start calling a building a skyscraper, and Chicago counts past 300, which is why two sources can disagree by 200 buildings and both be right.

The New York comparison gets asked a lot, so here it is plainly: New York has more. Above 150 m New York counts more than 325 buildings to Chicago's 137, about two and a half times as many. Chicago is second in the United States, and five of the fifteen tallest American buildings stand there, so it has fewer towers and a high share of very tall ones. The Loop is hemmed in by the river, the lake and Roosevelt Road, so they sit shoulder to shoulder. The cities page puts both counts next to Hong Kong and Dubai.

Why Chicago

On 8 October 1871 the Great Chicago Fire burned for two days and destroyed about 3.3 square miles, including most of the business district. It did two things that mattered for tall buildings. It cleared the most valuable land in the city at once, and it got the city to require fireproof construction, which ruled out the heavy timber framing that had just burned.

Then came the demand. Between 1880 and 1890 Chicago grew from just over 500,000 people to almost 1.1 million, companies were moving their offices downtown away from their factories, and every rail line in the region fed into the Loop. Office space ran short and the land got expensive. Cass Gilbert's description of a skyscraper is the whole economic argument in one sentence: a machine designed to make the land pay.

The technical means arrived at the same moment. The Bessemer process had made structural steel cheap enough to build with by the 1880s, the safety elevator was 30 years old, and Chicago engineers had worked out the floating raft foundation a heavy building needs on soft lake clay. In 1885 William LeBaron Jenney put the pieces together in the Home Insurance Building: 55 m and 12 floors, with the weight carried on an iron and steel frame and the masonry walls hung on it. It is usually called the first skyscraper, and the argument over that title is a real one, covered on the first skyscraper page and the page on who invented it. It was demolished in 1931.

Jenney's office trained the next generation. Daniel Burnham, William Holabird and Louis Sullivan all passed through it, and with Dankmar Adler and John Root they became the Chicago School: steel frames, wide plate glass in the Chicago window, ornament kept to the parts a passerby can see. Sullivan gave the movement its motto in an 1896 essay, "form ever follows function", later clipped to form follows function. His own buildings show what he meant by it better than the slogan does.

The famous ones

The Rookery (1888), by Burnham and Root, is 11 stories of masonry and iron around a light court that Frank Lloyd Wright remodeled in 1905.

Tribune Tower (1925) came out of a competition that drew 260 entries. Raymond Hood and John Mead Howells won with neo-Gothic buttresses at the crown, beating Eliel Saarinen's cleaner design that architects have argued for ever since.

Marina City (1964), Bertrand Goldberg's pair of corncob towers on the river, put apartments in the round on a concrete core, a bet that people would live downtown while the downtown population was falling.

875 North Michigan Avenue, still called the John Hancock Center by most of the city, reaches 344 m and opened in 1969. Its external X-braces are the structure, not decoration: Fazlur Rahman Khan's braced tube let the tower go up with far less steel than a conventional frame.

Aon Center (1973), 346 m, was clad in Italian marble that cracked in the Chicago winter. All of it was replaced with granite between 1990 and 1992, for close to half what the building cost to build.

Willis Tower

Willis Tower is the tallest building in Chicago at 442 m, finished in 1973 for Sears, Roebuck and Company and known as the Sears Tower until 2009. It held the world record for 25 years, until the Petronas Twin Towers took it in 1998 on their spires. Bruce Graham and Fazlur Rahman Khan of Skidmore, Owings & Merrill designed it as nine square tubes bundled together, stopping at different heights to give the stepped profile. That bundled tube went on to carry the Burj Khalifa.

The Skydeck sits on the 103rd floor, 412 m up, and takes about 1.7 million visitors a year. The glass-bottomed boxes people search for as the Chicago building with a glass floor are the Ledge: four opened in July 2009, cantilevered roughly four feet out from the facade, with a fifth added in 2022. Each holds five tons.

Seeing them

Most visitors see the skyline from the water. The Chicago Architecture Center runs a 90-minute river cruise along all three branches of the Chicago River, covering more than 50 buildings, narrated by volunteer docents who train for hundreds of hours first. Boats leave from the Riverwalk at Michigan Avenue and Wacker Drive. The high observation decks are the Skydeck and 360 Chicago in the Hancock.