Opening Day Procession for NMAI, by Long, Eric, September 21, 2004, Smithsonian Archives - History Div, View of the procession of Native American down the National Mall as part of the opening celebration of the Smithsonian's National Museum of the American Indian on the National Mall in Washington, D.C. Members of the Nakota Sioux Nation are nearest the camera, walking down Madison Drive, past the National Gallery of Art main building (on the right) with the National Museum of Natural History in the distance. This event was the largest gathering of Native Americans in history..