Smithsonian Institution Building Smithsonian Institution Building The Smithsonian Institution Building, located near the National Mall in Washington, D.C. behind the National Museum of African Art and the Sackler Gallery, houses the Smithsonian Institution's administrative offices and information center. The building is constructed of Seneca red sandstone in the faux Norman style (a 12th-century combination of late Romanesque and early Gothic motifs; built in the Gothic and Romanesque revival styles) and is nicknamed The Castle. It was completed in 1855 and designated a National Historic Landmark in 1965. The Castle was the first Smithsonian building, designed by architect James Renwick, Jr., whose other works
Smithsonian Institution History was the Hirshhorn Museum and Sculpture Garden, which opened in 1974. The National Air and Space Museum, the Smithsonian's largest in terms of floor space, opened in June 1976. Eleven years later, the National Museum of African Art and the Arthur M. Sackler Gallery opened in a new, joint, underground museum between the Freer Gallery and the Smithsonian Castle. Reuse of another old building came in 1993 with the opening of the National Postal Museum in the 1904 former City Post Office building, a few city blocks from the Mall. In 2004, the Smithsonian opened the National Museum of