This enormous clifftop fortress, built in stages between 1634 and 1783, covers 27 acres (11 ha) and is one of the largest Spanish castles built in the Americas. Towering 150 ft (45 m) above the Atlantic, this wonderfully preserved marvel of military engineering was connected to Fortaleza San Felipe del Morro by bastions stretching along more than half-a-mile (1 km) of shore. Following the Spanish-American War (for further details see US Take-Over), this fortress was occupied by the US Army until 1961. Now a UNESCO World Heritage Site, it is managed by the US National Parks Service, whose rangers lead free tours.Calle Norzagaray • 787 729 6960 • Open 9am–6pm • Adm $5 for both Fortaleza San Felipe del Mono and Castillo de San Cristobal; free for under-15s • www.nps.gov/saju
Approached via a long, sloping ramp that curves through almost 90 degrees, the arched entrance gate dates from 1783 and is topped by a decorative cornice with twin globes.
The fortress’s parade ground was completed in 1783. It is lined with load-bearing casements which were used as barracks, powder magazines, and officers’ quarters fronted by a loggia (columned balcony).
The lonesome Garita del Diablo, built in 1634, overhangs the ocean at the tip of the triangular Fuerte del Espigón (Fort of the Point). Guards were stationed here to keep watch for approaching enemy intruders.
This battery took its present form in the 1890s, when gun emplacements were added in preparation for the Spanish-American War. The officers’ quarters were added later.
The simple Capilla de Santa Bárbara, on the west side of Plaza de Armas, is dedicated to Santa Barbara, the patron saint of artillerymen, to whom troops prayed for their safe-keeping.
This battery is the highest of seven lines of defence intended to protect the city from a land invasion. In 1797, its cannons were instrumental in repelling a British invasion led by Sir Ralph Abercrombie.
The barracks, on the east side of Plaza de Armas, were built atop five massive cisterns. Even today, the soldiers’ uniforms hang in the rooms, just as they did in the 18th century.
This artillery piece, developed by Spanish Captain Salvador Díaz Ordoñez, fired the opening shots of the Spanish-American War on May 12, 1898, against the USS Yale.
The 16-ft (5-m) thick walls rise over a wide moat intended to slow the advance of invaders and expose them to deadly fire from the sentry boxes above.
An extensive tunnel system connected the center of the fort to the defensive elements and allowed protected movement of troops and artillery. The tunnels were mined and could be detonated to deny the enemy access.
Puerto Rican legend has it that the Devil’s Sentry Box is named for a sentry who was snatched by the devil, and left behind only his musket and uniform. The truth seems to be that the soldier craftily abandoned his post for his loved one, but many locals still believe that the garita is haunted.