Castillo del Reloj is an 11th-century Muslim fortress, also known as Castillo Real, located in Calatayud as part of a five-castle fortified enclosure surrounding the upper city. The current remains date to the 14th century and feature two access doors, a rock-carved staircase, and medieval cellars. Despite its name, the castle lacks a clock tower—that structure collapsed in the early 20th century—though it retains a historic bell gifted by Pedro IV in 1366 that still rings at local festivals, serving as a Cultural Heritage Site since 2006.
