Turin is an Italian city of 883 702 inhabitants, capital of the homonymous city subway and the Piedmont region. Heart of a metropolitan area that counts almost 2 000 000 inhabitants on an approximate surface of about 2 300 km², the city of Turin is the fourth Italian municipality by population, the third complex economic-productive of the country and is one of the major university poles, artistic, tourist, scientific and cultural in Italy. In 1997 part of the historical center of Turin, together with the Valentino Castle, the Villa della Regina and the others possessions of the Savoy residences circuit in Piedmont, has been recognized World Heritage Site by UNESCO with the name of: Residences of the Royal House of Savoy.