Vatican City, officially Vatican City State, is a landlocked microstate within the Rome metropolitan area of Italy. With an area of just over 44 hectares (108.7 acres), and a population of about 825, it is the smallest sovereign state in the world by both area and population. However, formally it is not sovereign, with sovereignty being held by the Holy See. It is an ecclesiastical or sacerdotal-monarchical state (a type of theocracy) ruled by the bishop of Rome—the Pope. The highest state functionaries are all Catholic clergy of various national origins. Vatican City is distinct from the Holy See, which dates back to early Christianity and is the main episcopal see of 1.3 billion Latin and Eastern Catholic adherents around the globe. The independent city-state, on the other hand, came into existence in 1139 as a feudal enclave of the Italian peninsula's secular rulers and the papacy, and has existed as such since the return of the popes from Avignon in 1377.
The territory of Vatican City is composed of two principal parts: the Vatican Hill, which makes up the independent state, and the area known as Vaticanum extra muros ("Vatican City outside the walls"), which is part of the city of Rome but under direct papal jurisdiction. The Vatican Hill is a hill located across the Tiber river from the Seven Hills of Rome. It is the location of St. Peter's Basilica, the Apostolic Palace, the Sistine Chapel and the Vatican Museums. The Vatican Hill is home to the Pope and the Catholic Church's central administration, the Roman Curia. Vatican City is surrounded by a 2-meter (6.6 ft) high stone wall, fortified by Bastion fortresses.
The state has no armed forces, and the police force consists of the Swiss Guard, a small ceremonial force maintained by Switzerland. Vatican City has its own postal system, fire brigade, bank, pharmacy, newspaper and television station. It also has a small but well-equipped hospital. The Vatican Library and the Vatican Observatory are among the scientific institutes operated by the state.