Castillo San Cristóbal (San Juan)

Castillo San Cristóbal (English: Saint Christopher Castle) is a fortress in the Old San Juan historic quarter of San Juan, the capital municipality of Puerto Rico, known for being the largest fortification built by the Spanish in the New World. Dating back to defense expansions following attacks by the English in 1598 and Dutch in 1625, it was first constructed in 1634 as the Caballero de San Miguel (Saint Michael Cavalier) and the Garita del Diablo ("devil’s sentry box"). Over the next 150 years, especially in the reign of King Charles III of Spain, it continued to be developed into a bastion fort with outer ravelins and batteries to reach its largest size in 1783. Rising 150 ft from the Atlantic shoreline, the three-level edifice stands on a hill at the northern coastline of San Juan Islet, guarding the land entry to Old San Juan. Alongside El Morro, La Fortaleza, and other forts part of the Walls of Old San Juan, it protected strategically and militarily important Puerto Rico, or La Llave de las Indias (The Key to the Indies), from invasion by competing world powers during the Age of Sail. It was designated a World Heritage Site by UNESCO in 1983.