This photograph was made to depict the Bollman Iron Truss Bridge. The Bollman Truss Bridge is the only known remaining example of the revolutionary all-iron truss system patented by Baltimore engineer Wendell Bollman in the mid-19th century. Constructed in 1869, the bridge was moved to its current site in 1888 and was in use until 1915. Designated a National Historic Landmark in 2000, it is now utilized as a pedestrian bridge.