Cagliari 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 about 150,000 inhabitants, while its metropolitan city (including Cagliari and 16 other nearby municipalities) has more than 431,000 inhabitants. According to Eurostat, the population of the Functional urban area, the commuting zone of Cagliari, rises to 476,974. Cagliari is the 26th largest city in Italy and the largest city on the island of Sardinia.

The Cagliari area has been inhabited since the Neolithic. It occupies a favourable position between the sea and a fertile plain and is surrounded by two swamps (which provides defence against attacks from the inland). There are high mountains nearby, to which people could evacuate if the settlement had to be given up.

More Info: en.wikipedia.org