The fortress was never used for its original intended purpose of artillery defense against external invasion due to rapid advancements in military technology.
During the 1938 escape, 792 prisoners managed to break out of the facility, though only three reached the French border.
The site occupies the entire summit of Mount Ezkaba at an elevation of approximately 895 meters.
The prison was officially closed in 1945, but the site was used as a military barracks until 1987.
The fortress design includes a triple-walled defense system that follows the irregular topography of the mountain peak.
Fuerte de Alfonso XII, commonly known as Fuerte de San Cristóbal, is an extensive 19th-century military fortress situated atop Mount Ezkaba, providing panoramic views of the Pamplona basin. Constructed between 1878 and 1919, the facility covers over 600,000 square meters and was primarily designed to protect the northern border of Pamplona. The structure features a complex system of defensive moats, subterranean galleries, and interconnected courtyards built into the mountain slope. It served as a notorious prison following the Spanish Civil War, housing thousands of political prisoners. A significant mass escape occurred here in 1938, involving nearly 800 inmates, which remains one of the largest prison breaks in Spanish history. The site was declared an Asset of Cultural Interest in 2001. Today, the complex remains largely abandoned and closed to the public, though the exterior grounds are accessible to hikers and cyclists.
The perimeter of the outer wall facing the south, which offers the widest view of the Pamplona city skyline.
Wear sturdy hiking boots, as the trails leading up to the fortress are steep and often covered in loose gravel.
Bring your own water and supplies, as there are no services, shops, or facilities at the summit.
Check weather reports beforehand; the summit is exposed, and high winds are frequent.
Do not attempt to enter the fenced-off or blocked areas of the fortress, as the interior is structurally unstable and prohibited.
The interior of the fortress is permanently closed to the public due to its state of ruin.
Respect the site as a memorial to the prisoners who suffered there; stay on designated paths and do not attempt to enter sealed structures.
