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,
Flag of Sardinia and Torres or Logudoro; each one developed its own coat of arms. When, with the appointment of the King of Aragon as King of Sardinia, the island again became one united kingdom, only the Judicatus of Arborea survived, and fought for a century against the Kingdom of Sardinia for supremacy. According to some, the flag derives from Alcoraz victory of 1096, is linked to the Crown of Aragon, and represents the Spanish Reconquista against the Moors who occupied most of the Iberian Peninsula. It is composed of the cross of St. George, also a symbol of the Crusaders fighting in