The fortresses of San Juan and the defence of the Spanish Caribbean

Spain began the fortress of El Morro in 1539 to guard San Juan's harbour, an entry to its Caribbean sea lanes. The walled city drove off Francis Drake in 1595, fell for a few months to the Earl of Cumberland in 1598, held out against a Dutch siege in 1625 and repelled a British invasion in 1797. Its forts are now run by the US National Park Service.