875 North Michigan Avenue (John Hancock Center)

The tapering black X-braced tower with twin antennas; the roof is 344 m, the antennas reach 457 m.

It is a black tower that tapers as it rises, wrapped in giant X-shaped braces. The building holds offices, restaurants and about 700 condominiums, and when it opened it had the highest residence in the world. Today it is the fifth tallest building in Chicago and the fourteenth tallest in the United States.

The big X

The giant X braces on the outside are not just decoration, they are a key part of the structure. They make the tower stiff against wind with less steel than a more ordinary frame, which is why the building could be so tall and slim. The idea of a braced tube came from Fazlur Rahman Khan, a Bangladeshi-American engineer who also helped design other record-setting towers.

Building troubles

Wolman conceived the project in late 1964, and the John Hancock Mutual Life Insurance Company financed it. In 1967 work stopped because of a flaw in an innovative method of pouring concrete in stages. At 20 stories, engineers found the soil settling as much as they had expected for all 99 stories. The owner, Jerry Wolman, went bankrupt, and John Hancock took over the project. The first resident, building engineer Ray Heckla, moved in with his family in April 1969, before the building was finished.

At the top and in the middle

The 360 Chicago observatory has a 360-degree view reaching up to four states and over 80 miles. It has TILT, a moving platform that leans visitors out over the edge at a 30-degree angle, and Chicago's only open-air SkyWalk. The 44th-floor sky lobby has the highest indoor swimming pool in the United States. The 95th-floor restaurant closed in late 2023. The movie Poltergeist III was set here in 1988. In 2018 John Hancock Insurance asked for its name to be removed.

On the globe

The model shows the tapering black tower with X-shaped braces and two antennas. Look for the big crossing beams.