Castillo San Cristobal

Standing guard at Old San Juan’s eastern gate, Castillo San Cristóbal was built to protect the city against land attacks. As the largest Spanish fortification in the New World, it now forms part of the San Juan National Historic Site. The fortress sprawls across a vast area, its stone walls and strategic layout offering a glimpse into the military architecture of the colonial era. Visitors can explore the complex, which includes tunnels, barracks, and artillery positions, and enjoy panoramic views of the bay and the nearby Castillo San Felipe del Morro.