By World War II, the Yard was the largest naval ordnance plant in the world. The weapons designed and built there were used in every war in which the United States fought until the 1960s. At its peak, the Yard consisted of 188 buildngs on 126 acres (0.5 km²) of land and employed nearly 25,000 people. Small components for optical systems, and enormous battleship guns were all manufactured here. In December 1945, the Yard was renamed the U.S. Naval Gun Factory. Ordnance work continued for some years after World War II until finally phased out in 1961. Three years later, on July 1, 1964, the activity was redesignated the Washington Navy Yard. The deserted factory buildings began to be converted to office use.