The South Yard behind the Smithsonian Institution Building, the Castle, is bordered on the east by the Arts and Industries Building and west by the Freer Gallery of Art. In the late 19th century, it was the site of small buildings for the Smithsonian Astrophysical Observatory, Taxidermy Studio, National Zoological Park, and Aerodrome Studio. After World War I, a Quonset hut housed the National Air Museum (today, the National Air and Space Museum), next to the Radiation Biology Laboratory (today, the Smithsonian Environmental Research Center) greenhouses. By the 1960s, “Rocket Row” along the Arts and Industries Building’s east side showcased the latest in space technology. In 1976, the South Yard was converted to a Victorian Garden to welcome visitors. In the 1980s, the area was excavated to create the Quadrangle Complex, with underground buildings for the National Museum of African Art, Arthur M. Sackler Gallery, and S. Dillon Ripley International Center. Pavilion entrances to these buildings are nestled within the Enid A. Haupt Garden.