Aon Center

The white granite building with 83 floors rises 346 meters into the Chicago skyline at 200 East Randolph Street in the Loop district.

Completed in 1973 as the Standard Oil Building, it underwent a complete exterior transformation in 1992 when the original marble cladding was replaced with granite.

The structure represents a shift in corporate architecture, serving as headquarters for three major companies: Standard Oil, Amoco, and currently Aon Corporation.

The skyscraper contains 50 elevators serving both its 83 above-ground floors and 5 underground levels, with direct access to Chicago's underground walkway system.

The building required the largest architectural recladding project in history, replacing 43,000 marble slabs with granite panels during the early 1990s.

Location: Chicago

Inception: 1973

Architects: Edward Durell Stone

Official opening: 1973

Architectural style: modern architecture

Floors above the ground: 83

Floors below the ground: 5

Elevators: 50

Height: 69.8 m

Address: East Randolph St. 200, Chicago, Illinois, USA

GPS coordinates: 41.88528,-87.62139

Latest update: May 26, 2025 19:54