The National Air and Space Museum (NASM) of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world in 161,145 square feet (14,970.9 m2) of exhibition floor space. It was established in 1946, as the National Air Museum, and opened its main building in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and spaceflight, as well as planetary science and terrestrial geology and geophysics. Almost all space and aircraft on display are originals or backups to the originals. It operates an annex, the Steven F. Udvar-Hazy Center, at Dulles International Airport. The museum currently conducts restoration of its collection at the Paul E. Garber Preservation, Restoration, and Storage Facility in Suitland, Maryland.

Because of the museum's close proximity to the United States Capitol, the Smithsonian wanted a building that would be architecturally impressive but would not stand out too boldly against the Capitol building. St. Louis-based architect Gyo Obata of Hellmuth, Obata and Kassabaum designed the museum as four simple marble-encased cubes containing the smaller and more theatrical exhibits, connected by three spacious steel-and-glass atria which house the larger exhibits such as missiles, airplanes and spacecraft. The mass of the museum is similar to the National Gallery of Art across the National Mall, and uses the same pink Tennessee marble as
the National Gallery. Built by Gilbane Building Company, the museum was completed in 1976. The west glass wall of the building is used for the installation of airplanes, functioning as a giant door. Hellmuth, Obata and Kassabaum also designed the Steven F. Udvar-Hazy Center in Virginia.