Built under Castilian rule in the 13th and 14th centuries on the remains of a Moorish predecessor, this fort-cum-palace was where the Catholic Monarchs, Fernando and Isabel, made their first acquaintance with Columbus in 1486. One hall displays some remarkable Roman mosaics, dug up from Plaza de la Corredera in the 1950s. The Alcázar's terraced gardens – full of fish ponds, fountains, orange trees and flowers – are a delight to stroll around.
At 9pm (except Mondays) there's a popular multimedia show featuring lights, flamenco music and dancing fountains called Noches Mágicas en el Alcázar (Magic Nights in the Alcázar; adult/child €6.50/free). While here, it's also interesting to visit the nearby Baños del Alcázar Califal, the impressive 10th-century bathhouse of the Moorish Alcázar.