The Polvorín de San Gerónimo (San Geronimo Powderhouse) is one of four gunpowder and ammunition storage buildings the Spanish built in the 18th century as part of San Juan's defensive system. The brick and masonry building, which has a rectangular plan, was constructed between 1769 and 1772 by Spanish Military Engineer Juan Francisco Mestre. The building's vaulted interior is supported on both sides by 10 massive buttresses. In 1935, the powderhouse was used as the Museum of Natural History and in 1945 it served as a zoo. The building was restored between 1992 and 1994 by the Puerto Rico National Parks Trust.

The Polvorín de San Gerónimo, part of the Linea Advanzada, is located within the Luis Muñoz Rivera Park, east of the city of San Juan, Puerto Rico. The Polvorín de San Gerónimo has also been documented by the Historic American Buildings Survey.

Information and photos courtesy of the National Register for Historic Places Puerto Rico Travel Itinerary, a subsidiary of the National Park Service.

Credits and Sources:

Nancy Cox, Undergraduate Student, University of West Florida