D.C. Government buildings on the National Register of Historic Places in Washington, D.C. Members of the Cultural Alliance of Greater Washington Neoclassical architecture in Washington, D.C. Philatelic museums in the United States History museums in Washington, D.C. Industry museums in Washington, D.C. Smithsonian Institution museums Postal history of the United States United States 1993 establishments in Washington, D.C. Museums established in 1993