Puerto Rico is the Caribbean island home to Castillo San Felipe del Morro in San Juan.
Known commonly as El Morro, the fortress stands on a promontory at the entrance to San Juan Bay. Spain built and expanded it over several centuries to protect the strategic harbor and the city from naval attacks. Its thick walls, elevated gun positions, and distinctive sentry boxes reflect the engineering of a major early modern coastal fortress.
Construction began in the sixteenth century, and the complex was repeatedly enlarged as artillery and military requirements changed. El Morro played a role in attacks and sieges involving European powers and later became part of the historic landscape of San Juan.
The fortress is often confused with Castillo San Cristóbal, another major Spanish fortification in San Juan. Both are on Puerto Rico, but El Morro guards the bay entrance while San Cristóbal defended the landward side of the city.