World's tallest reinforced concrete building when completed; surpassed two years later by Central Plaza in Hong Kong.

The building's top is a large cylinder surrounded by four smaller cylinders. One prototype design included four spires around the circumference.

The five cylinders on top are lit at night by 1,852 fluorescent tubes, creating a light bright enough to compete with the full moon.

The front lobby is a large two-level winter garden with glazed palm trees and an 86-foot high glass roof.

Raymond Kaskey's bronze sculpture "Gem of the Lakes" looks over the winter garden from the Wacker entrance. It depicts a large Neptunian figure drying himself over a seashell fountain.

The lower level of the winter garden was designed to connect via underground passageway to Union Station.

311 South Wacker Drive is the tallest building in the world known only by its street address.

Two towers similar to this one were planned for the lots on either side. Both sites are reserved for future development, and the northwest plot is a temporary park.

The canopy over the sidewalk in front of the winter garden was added to the building in 2002.

The lantern at the top changes colors for various holidays and special events.