located about 15 miles south of the village of los yebnes is the beautiful castillo de guadalerzas. it was built during the reign of alfonso VII by the order of calatrava in 1178 as a hospital and a defensive position. in 1572 king felipe II sold the castillo to cardinal siliceo who converted it into a school. today it is a private residence. it can be seen from a small park on the side of hwy N401.