This large Islamic fort was built in the mid-9th century on a site already occupied by the Romans and Visigoths, probably becoming the first ever alcazaba in Al-Andalus. In the middle of the sprawling complex, its pretty goldfish-populated aljibe (cistern) reuses Visigothic marble, flower motifs and stone slabs, while the ramparts look out over the Puente Romano and the Río Guadiana. The 15th-century monastery in the northeast corner now serves as regional government offices.