At different times in the 20th century, the U.S. had about 25 military or naval installations in Puerto Rico, some very small ones, as well as large installations. The largest of these installations were the former Roosevelt Roads Naval Station in Ceiba, the Atlantic Fleet Weapons Training Facility (AFWTF) on Vieques, the National Guard training facility at Camp Santiago in Salinas, Fort Allen in Juana Diaz, the Army's Fort Buchanan in San Juan, the former U.S. Air Force Ramey Air Force Base in Aguadilla, and the Puerto Rico Air National Guard at Muñiz Air Force base in San Juan.