Built in 1328 by Alfonso XI on the foundations of the earlier Moorish caliphal palace, the Alcázar served as a royal residence, the headquarters of the Spanish Inquisition for three centuries, and later a prison. The interior is sober — bare stone halls, a few good Roman mosaics — but the gardens are the real draw: long reflecting pools flanked by cypresses, fountains, and tiered flowerbeds running down to the Guadalquivir.
Climb the Tower of Homage for a panorama over the old town. Open Tue–Sun; small admission fee, free on Wednesdays for EU citizens.