The Gibraltar of the Caribbean
Puerto Rico’s geographic position at the western edge of the Caribbean made San Juan one of the key frontier outposts of Spain’s West Indies dominions. San Juan National Historic Site includes Castillo San Cristóbal, Castillo San Felipe del Morro, Fortín San Juan de la Cruz known locally as El Cañuelo, and three fourths of the city walls.
Did You Know?
Castillo San Cristóbal is the biggest fortification built by the Spanish in America. It's construction began in 1634 and took approximately 150 years.