Founded in 1846, the Smithsonian is the world's largest museum, education, and research complex, with 21 museums, 21 libraries, the National Zoo, numerous research centers, and several education units and centers.
Completed in 1855, the Smithsonian Institution Building (The Castle) is our signature building. The Castle closed Wednesday, Feb. 1, 2023, for its first major renovation in more than 50 years. The renovation is expected to last about five years.