Papal Palace (Palais des Papes) in Avignon
Avignon was home to 7 popes (1309-1377) and 2 anti-popes (1378-1403), when Frenchman Clement V, due to his fear of assassination, refused to relocate to Rome after his election as Pope.
Constructed on the site of a bishop's palace, in two phrases as the old and new palaces, it is a Medieval fortress with thin vertical arrow slits.