Rome is the capital city of Italy and Lazio, and is Italy's largest and most populous city, with 2,705,317 residents. Rome has an urban area of 3,457,690 as well as a metropolitan area of 4,013,057 inhabitants. It is located in the central-western portion of the Italian peninsula, on the Tiber river. Rome's history as a city spans over two and a half thousand years, as one of the founding cities of Western Civilization. Even outside of the history of the Roman Empire, Rome has a significant place in the story of Christianity up to the present day, for it endures as the home of the papacy. The worldwide Roman Catholic Church is administered from the Vatican City, run by the Holy See as an independent enclave and the world's smallest sovereign state. Today, Rome is a modern, cosmopolitan city, and the third most-visited tourist destination in the European Union. Due to its influence in politics, media, the arts and culture, Rome has been described as a global city. Rome's international airport, Fiumicino, is the largest in Italy and the city hosts the head offices of the vast majority of the major Italian companies, as well as the headquarters of three of the world's 100 largest companies: Enel, ENI, and Telecom Italia. As one of the few major European cities that escaped World War II relatively unscathed, central Rome remains essentially Renaissance and Baroque in character. The historic centre of Rome is listed by UNESCO as a World Heritage Site.