After the U.S. entered World War II in 1941, fear of enemy agents led the government to create an internment camp system run by the Immigration and Naturalization Service to hold Japanese, German, and Italian nationals arrested in the U.S. and Hawaii and in Peru and other Latin American countries until they could be exchanged for American detainees. Three of these camps were in Texas, at Kenedy, Seagoville, and Crystal City. Converted from an existing migratory labor camp, Crystal City was the largest internment facility in the U.S. and the only one built exclusively for families. Its original 200-acre site later expanded to almost 500 acres with agricultural areas and support facilities, while the main 100-acre living compound was enclosed by a 10-foot barbed wire fence with guard towers and spotlights. With 700 buildings, it functioned like a small town, containing family housing, schools, a hospital, shops, warehouses, markets, and recreation areas. Although intended for Japanese internees, it also held Germans and a few Italians. Its population averaged 2,800 during the war and peaked at almost 3,400 in December 1944, two-thirds of them Japanese. After the war, the government paroled internees throughout the U.S. or sent them to their home countries. Crystal City remained the only camp still operating by June 1946, officially closed on February 27, 1948, and its property was transferred to the city and school district.