A fortress on a rock where the Eresma and Clamores valleys meet, chosen as a residence by many Trastámara monarchs; its keep is often compared to the prow of a ship. Allow 40–45 minutes for the Palace and Museum. Buy tickets ahead for weekends and holidays, when they often sell out, especially those that include the Tower of Juan II.
A Roman aqueduct from the 1st century AD with 166 granite arches built without mortar, held up by the balance of its stones. The system runs about 15 km, one kilometre of it as arcade, and reaches 28 metres at its highest point in Plaza del Azoguejo.