Walk El Morro & Old San Juan's City Walls
Climb through Castillo San Felipe del Morro, the 16th-century Spanish citadel jutting into the Atlantic with its ring of sentry-box garitas and a vast kite-flying esplanade -- the single signature image of San Juan, a UNESCO World Heritage site steps from the pier. Your $10 ticket also gets you into the larger Castillo San Cristobal for 24 hours, so you can pair the two forts with a self-guided wander of the blue-cobblestoned colonial streets and city walls. Open 9am-6pm (last entry 5pm), cashless entry.