The National Air and Space Museum (NASM) in part of the Smithsonian Institution and holds the largest collection of historic aircraft and spacecraft in the world in 14,970.9 square feet of exhibition floor space. It was established in 1946, as the National Air Museum and opened its main building near L'Enfant Plaza 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.