Built by the Smithsonian Institution for the Louisiana Purchase Exposition in St. Louis, the 1904 World's Fair Flight Cage was at the time the largest bird cage ever built and became one of the exposition's most popular attractions. After the fair, although the Smithsonian planned to move it to the National Zoo in Washington, D.C., citizens of St. Louis successfully rallied to keep it in Forest Park. The structure later served as the centerpiece for the creation of the Saint Louis Zoo in 1913, and it remains an integral part of the zoo as well as one of the largest free flight aviaries in the world. Over the years it has housed many bird species, including exotic birds, and today it provides habitat for native birds found in the swamps of Missouri.