Owned by the monks of the Liren Islands, Castre Castle was built on top of Suquet Hill in the eleventh century in order to protect the port and coast of Cannes from invasions, and was later converted into a historical museum. One of its distinguishing features is the amphitheater, which offers wonderful views of the Gulf of Cannes and Estelle, and in the middle of the castle's central courtyard stands a stunning square watch tower 21 meters high.