12 Fortified Port Cities Where History Meets the Ocean Waves

8. San Juan, Puerto Rico: Caribbean Sentinel of an Empire

Guarding the gateway to the Spanish Caribbean, San Juan’s fortifications are a monumental display of colonial military architecture. The formidable Castillo San Felipe del Morro, with its six staggered levels, and the sprawling Castillo San Cristóbal were engineered over centuries to protect the strategic port from sea and land attacks by European rivals and pirates. Walking the ramparts of these UNESCO sites offers breathtaking ocean vistas and a deep dive into the island's pivotal role in the Spanish Empire’s New World defense network.