Also known by the name of Su Casteddu, located in the Monte Baranta hill of the same name, about 3 km from the town, in the direction of Alghero, it is situated on a rocky plateau that dominates the entire Nurra and from which it is possible to admire the surrounding naturalistic landscape. Within this site of pre-Nuragic age (presumably dating from 2500-2000 BC.) there are several types of structures: the enclosure-tower, a mammoth fortress (unique in Sardinia) with a unique horseshoe shape; the wall, an imposing wall (97 meters long, 5 meters wide and an average of 2.5 meters high), which served a defensive function for the living area; the sacred area, a clearing characterized by the presence of a large megalithic circle and several menhirs (phallic-shaped trachyte slabs, symbols of fertility); the settlement, bounded by the wall, in which traces of the village huts are recognizable.