Castillo San Felipe del Morro, known simply as El Morro, once helped see off Sir Francis Drake. In 1595, the English privateer met the fortress’s guns and the metal chains stretched across its entrance, then sailed away without Puerto Rico.

It began in 1539 as a simple tower and grew into a Spanish military fortress guarding San Juan Bay. Its heaviest cannons sat in the middle, its lookouts watched from sentry boxes called garitas, and captured pirates ended up in its dungeons. It fought its last battle in 1898, when the US Navy bombarded it during the Spanish-American War. Today it is a UNESCO World Heritage Site.

VoiceMap’s Talking Buildings of Old San Juan tour saves El Morro for last. A governor’s mansion, a former asylum and a seaside cemetery narrate their own histories first, then the fortress takes its turn, speaking for itself.