Castle of Ulldecona Monument · Ulldecona, Montsià, Tarragona Fortified complex situated at the top of the Puig del Castell, in Ulldecona (Montsià), on the banks of the Sénia river, today the border between Catalonia and the Valencian Community. Probably of Arab origin, it passed in 1148 to the Montcada family of Tortosa; in 1173 it passed to the Order of the Hospital of Saint John of Jerusalem, which in 1180 was commissioned to build a new Christian castle. Situated on the frontier with the Muslims, it suffered continuous attacks, so that in 1191 the Hospitallers returned custody of it to the Montcada; it remained part of that frontier until the campaigns of James I in Valencia, begun around 1230, pushed the border south. It today consists of a doubly walled precinct, a round tower, another quadrangular tower of the Order of Malta, a church dedicated to the Virgin of the Angels, and ruins of other vanished buildings. Photo: No machine-readable author provided. Makinal~commonswiki assumed (based on copyright claims). (CC BY-SA 3.0) What to see and do in Ulldecona