Castello di San Michele

Lifted by a hill high above the city, this stout three-tower Spanish fortress northwest of the centre commands incredible city and sea views. Set in serene grounds, the 10th-century castle was built to protect Santa Igia, capital of the Giudicato of Cagliari, but is most famous as the luxurious residence of the 14th-century Carroz family. It now hosts exhibitions and cultural events. To get here, take bus 5 from Via Roma to the foot of the hill and then walk 800m to the castle.