Fortín San Juan de la Cruz (English: Fort Saint John of the Cross), most commonly known as El Cañuelo, was built on Isla de Cabras in the Palo Seco barrio of the municipality of Toa Baja, at the western end of the entrance to San Juan Bay, in Puerto Rico. The square coastal fort has massive sandstone walls that date back to the 1630s. Although the U.S. Navy bombarded the fort in 1898, the fort survived. Today the fort is part of the San Juan National Historic Site, which is listed as a UNESCO World Heritage Site and on both the National Register of Historic Places and the Puerto Rico Register of Historic Sites and Zones. The fort is not open to visitors, but it can be viewed from its exterior.