a US national institution that consists of several museums and centres for scientific research in Washington, DC. It was established in 1846 by the US Congress with money given by James Smithson (1765-1829), an English scientist. Its popular name is 'the nation's attic'. The 12 major museums, most of which are situated along the Mall (2), include the National Air and Space Museum, the National Gallery of Art, the National Museum of American Art, the National Portrait Gallery and the National Museum of American History. The Kennedy Center is an independent part of the Smithsonian.