Palacio de la Aljafería, Zaragoza

Originally built as a summer residence for the Muslim ruler of the area in the 11th century, Abu Jafar al-Muqtadir. It later became the palace of the Kings of Aragon. Its interior contains several buildings from different historical periods. There's a beautiful little mosque by the entrance, Pedro IV's palace, the spectacular palace of the Catholic Monarchs and the Troubadour Tower. The finely carved ceiling in the throne room is a work of art that contains the symbols of Isabel and Fernando: the arrows and the yoke tied with the Gordian knot. The Aragonese parliament meets in this building to debate issues of regional importance. Admission: adults EUR 3; groups (over 10) EUR 2; students and seniors EUR 1; children under 12 free. Free admission for everyone on Sundays.