Fort San Cristóbal, referred to as the “Gibraltar of the Caribbean,” is situated on the eastern side of Old San Juan. Work on the fort commenced in 1634 and took more than a hundred years to finish. It stands as one of the largest Spanish forts ever constructed and the mightiest in the Americas. Built to strengthen Spain's defense of Old San Juan's harbor, the fort safeguarded the island from land assaults. It features walls that rise 150 feet above the ocean, spans a vast 27 acres of terrain, and contains five distinct independent units that connect through tunnels. Each unit is taller and sturdier than the preceding one, employing a “defense-in-depth” strategy.
Down one of the tunnels, there exists the dungeon which houses a death cell. In the 17th century, this small room lacked electricity and air conditioning, only possessing a narrow window slit for light and ventilation. This cell was designated for inmates who were anticipating their execution. Soldiers employed iron handcuffs and anklets to bind prisoners to the walls. On the walls, one can observe drawings of five ships created by an artillery captain. The ships exhibit incredible detail, right down to the flags signifying which ones belong to the adversary.
The fort has stayed almost the same as it was in the late 18th century when building was completed. The fort was in operation until 1961 when the United States armed forces ceased utilizing it as a military installation. It subsequently came under the authority of the National Park Service and is now a park and museum. In 1983, it was designated as a World Heritage Site. You have the option to explore the site on your own or register for a ranger-led tour.
