Cagliari (, or ; ; ; ) is an Italian municipality and the capital of the island of Sardinia, an autonomous region of Italy. Cagliari's Sardinian name Casteddu literally means castle. It has nearly 150,000 inhabitants, while its metropolitan area (including Cagliari and 15 other municipalities) has more than 422,000 inhabitants. Cagliari is the 26th largest city in Italy and the largest city on the island of Sardinia.