Walk through centuries of history with visits to two massive and impressive fortresses-El Morro and San Cristóbal. Set on each end of Old San Juan, your drive takes you first to Fort San Felipe del Morro, the oldest Spanish fort in the New World. Standing guard at the entrance to San Juan, the six-story citadel boasts garitas, or sentry boxes, all around the fort's outer walls; cannons; and magnificent views. Following your tour, you'll rejoin your transportation and travel through historical Old Town filled with Spanish colonial buildings to Fort San Cristobal, one of the largest defenses ever built in the Americas. Take time to see the Chapel, genuine cannonballs, gunnery positions, and tunnels that offer a glimpse into the past. At the conclusion of your tour, you'll return to your ship; en route you'll stop and shop at the lovely Plaza Colon.