Rising above the cliffs of the Punta Prima headland, next to Es Pujols, this 18th-century watch and defence tower is the largest of the four that Formentera still preserves. Built in 1762 under the direction of military engineer Juan Ballester de Zafra, it protected the local population from pirate attacks. With its truncated cone shape, sentry box and parapet, it kept watch over passing vessels and raised the alarm with smoke and fire signals. Today it offers spectacular views towards Ibiza and the cliffs. The interior cannot be visited, but the surroundings are open to all: an unbeatable vantage point at sunrise and sunset.