Air and Space Building, South Yard, by Unknown, c. 1920s, Smithsonian Archives - History Div, The temporary metal building behind Smithsonian Institution Building, the "Castle," in the South Yard built in 1917 by the United States Signal Service for use during World War I. The shed was transferred to the Smithsonian in 1919 and served as the National Air Museum, now the National Air and Space Museum, for many years. It was demolished in 1975 in preparation for the Bicentennial of the American Revolution, Victorian Garden. In front of the Air Museum building is a French made Renault tank and a German howitzer..