Located at the entrance to the port of Mahón, the San Felipe Castle was built in the mid-16th century, following the design of the Italian engineer Juan Bautista Calvi. During the successive British dominations, the castle was expanded until 1782, when, after the Spanish siege, its surrender was secured, and Spain regained sovereignty through the Treaty of Amiens. King Charles III then ordered the demolition of the castle.
Some remnants remain on the surface, but the most impressive part of the visit lies underground: several levels of subterranean galleries built by the Spanish and the British during their respective occupations.
The castle bears witness to nearly two and a half centuries of tumultuous history. Visitors will marvel at the incredible human effort made in the 16th, 17th, and 18th centuries—an extensive labyrinth of underground galleries where three thousand British soldiers and civilians lived for six months during the Spanish conquest of 1782.