Excavation for Quad Construction, by Ploskonka, Jeffrey, 1984, Smithsonian Archives - History Div, Excavation in preparation for construction of the Smithsonian's $73.2 million underground complex on the Quad to include the National Museum of African Art, the Arthur M. Sackler Gallery, and the S. Dillon Ripley International Center. The Arts and Industries Building is in the background, and on the far left in the background is the Smithsonian Institution Building, the "Castle"..