The castle of Pedres;still impressive and inexpugnable despite the collapse of some parts;rises at the foot of a hill dominating the gulf of Olbia.Documented in 1339;in the second half of the 14th century it was alternatively under the rule of the Aragonese and the Giudicato di Arborea;it was definitely abandoned in the 15th century when the island was conquered by the Iberians.The only remains of this castle are a polygonal wall with the ruins of a square tower (10m high);two rooms and a small tank.