Fuerte de Lord John Hay, also known as Arroka Haundieta, is a 19th-century fortification perched at 211 meters on one of the peaks of Jaizkibel overlooking the Ría de Pasajes in Pasaia, Guipúzcoa. Named after the British naval officer Lord John Hay, this sandstone fortress was constructed to defend against terrestrial attacks and subsequently remodeled during the Last Carlist War, creating an L-shaped structure with lower access points and higher rear walls. The roughly rectangular fort originally housed three buildings—a barracks capable of accommodating 60 men, a powder magazine, and a kitchen—and stands as a testament to 19th-century Spanish military engineering.
