Antiguo Cuartel Militar Español de Ponce
 The Antiguo Cuartel Militar Español de Ponce or El Castillo (English: Old Spanish Military Headquarters in Ponce or The Castle) is the only structure directly related to the events of the land defense of Puerto Rico during the 1898 American invasion of the Island. The historic building dates from 1894 and is located on Castillo street in Ponce Puerto Rico in the city's historic district. The structure was listed on the U.S. National Register of Historic Places on May 14 1987.