The Smithsonian Institution

NATIONAL MALL. The Smithsonian – for many, the image of the 19th-century sandstone "Castle" immediately springs to mind. The Institution itself is larger than most realize (19 museums and the National Zoo in DC alone) and granting only one day to "do the Smithsonian" is a mistake. Always-popular stops are the National Air & Space Museum and the National Museum of American History (closed until Summer 2008); however, the beautiful National Museum of the American Indian has emerged as a hot attraction, and the Steven F. Udvar-Hazy Center near Washington-Dulles serves as a fascinating repository of nearly 80% of the Smithsonian's air and space collection. METRO: Smithsonian