Sardinia world (22 centenarians/100,000 inhabitants). Sardinia is the first discovered Blue Zone, a demographic and/or geographic area in the world with an oversize concentration of centenarians and supercentenarians. In 2016 there were 50,346 foreign national residents, forming 3% of the total Sardinian population. The most represented nationalities were: Sardinia's most populated cities are Cagliari and Sassari. The Metropolitan City of Cagliari has 431,302 inhabitants, or about ¼ of the population of the entire island. Eurostat has identified in Sardinia two Functional Urban Areas: Cagliari, with 477,000 inhabitants, and Sassari, with 222,000 inhabitants. Sardinia is one of the five Italian autonomous regions,
Iglesias, Sardinia Iglesias, Sardinia Iglesias ( ; ) is a "comune" and city in the province of South Sardinia in Italy. It was co-capital of the province of Carbonia-Iglesias with Carbonia, and the province's second-largest community. Under Spanish control Iglesias was one of the most important royal cities on Sardinia, and it is the seat of the Roman Catholic Diocese of Iglesias. At an elevation of in the hills of southwestern Sardinia, it was the centre of a mining district from which lead, zinc, and silver were extracted. Iglesias was also a centre for the distillation of sulfuric acid. The area around