This fortress is generally thought to have been built in 1112, even if recent digs tend to prove that the structures currently visible date back to the Aragonese conquest. The castle occupies 2 000m2 and has a perimeter of 300m and seven polygonal and square towers. The church that lies within the castle walls, Nostra Signora de sos Regnos Altos, has retained a handsome series of Provençal Tuscan-style frescoes from (1350-1370). The stairs east of the castle lead down to the Sa Costa quarter.