Natural History Building, as seen from The Mall, by Unknown, May 3, 1917, Smithsonian Archives - History Div, The United States National Museum, now known as the National Museum of Natural History, building viewed across the Mall from one of the Smithsonian Institution Building's towers . The Old Post Office Pavilion can be seen in the background. In between the trees, a car has backed into a space and parked in front of the USNM building on Madison Drive..