A small concrete military structure tied to Formentera's wartime past and to the mark left by the Civil War and its aftermath on the Balearic Islands. It stands in the north of the island, beside the Estany Pudent and the road from Sant Ferran to La Savina, very close to the remains of the seaplane base that the lagoon hosted between 1937 and 1953. An austere structure set within a protected natural area, part of the Parc Natural de Ses Salines. There are no information panels or guided tours, so it is best viewed respectfully from the outside, ideally at sunrise or sunset.