This is a model of the Cortland Street Bridge in Chicago, Illinois. The first trunnion bascule bridge was built in Chicago at Cortland Street in 1902. This is the bridge type Chicago engineers are perhaps most famous for. The trunnion bascule has two bridge leaves hinged on opposing riverbanks. This bridge's truss superstructure was built by the American Bridge Company, Lassig Plant. The bridge was designated as an ASCE Civil Engineering Landmark in 1981, and a Chicago Landmark in 1991.