Of the village of Serru, in the vicinity of Gonnos, little is known. We know that the Saracen raid of 1610 marked its end. Some speculate that the survivors had taken refuge, in part, in Arbus and in greater part in Gonnese territory.
Some traces of this village still remain in the ruins of the country church of San Cosimo, along the road from Gonnosfanadiga to Arbus, on the side opposite the tomb of the giants of San Cosimo. About 50 meters away stands the Nuraghe of San Cosimo. The church, long a source of dispute among neighboring municipalities, was originally dedicated to St. John the Baptist.
About 50 meters from this is the nuraghe Su Bruncu ‘e S’Orcu and about 380 meters away is the Tomb of the Giants of the same name, still well preserved though partially buried.
