The Michigan Avenue bridge was originally conceived as a part of Daniel Burnham's 1909 Plan of Chicago. The double-decker double-leaf trunnion bascule bridge was designed by architect Edward H. Bennet and engineers Thomas D. Pihlseldt and Hugh Young, and opened in 1920. The bridge provided an impressive gateway to North Michigan Avenue and contributed to it's development as one of city's premier throughfares. It was designated a Chicago Landmark in 1991. Each bridge tower is adorned, in 1928, with a bas relief sculpture, of carved limestone, commemorating important events in Chicago history.

Southwest Tower: Defence - By Henry Hering. Erected by the B.F. Ferguson Monument Fund. Houses the McCormick Bridgehouse and Chicago River Museum.

Southeast Tower: Regeneration - By Henry Hering. Erected by the B.F. Ferguson Monument Fund. Houses equipment to operate the bridge.

Northwest Tower: Pioneers - By James Earle Fraser. gift of William Wrigley Jr. Houses equipment to operate the bridge.

Northeast Tower: Discoverers - By James Earle Fraser.

The Discoverers commemorates four European explorers who passed through the Chicago area in the late 1600's. Louis Joliet and Father Jacques Marquette were the first non-native people known to explore the map of Mississippi River system. They traveled down the Chicago River in 1674 on their return to the Great Lakes from the Mississippi. Rene Robert Cavelier, Sieur De LaSalle, and Henri De Tonti explored the entire Mississippi River basin between 1679 and 1682.

Source, dont certains éléments sont présentés de façon différente.