Castillo San Felipe del Morro, commonly known as El Morro, is a historic 16th-century Spanish fortress located at the entrance of San Juan Bay in Puerto Rico. Built to defend the island against naval attacks, it features massive stone walls, sentry towers, and strategic cannon emplacements that overlook the Atlantic Ocean. Today, it stands as a UNESCO World Heritage Site and popular tourist attraction, offering visitors panoramic views and a glimpse into Puerto Rico’s colonial military history.