On this high hill bristling with ruins, the crumbling fortress of Calatrava nonetheless remains awe-inspiring. Of Arabic origins, it became the seat of the Order of Calatrava of solider monks founded during the Reconquest. You have to go through two of the three perimeter walls, to reach the restored church, lit by an immense rose window. It has kept its fine brick vaulting, described as "swallow's nest", probably the work of Moorish prisoners. The castle lies within the third perimeter wall.