Vatican is an independent state, the residence of the Pope. However, tourists are more interested not in its state structure but in its sights, such as the Basilica of St. Peter with its large colonnade and the Vatican museums.
In ancient times Vatican was a swampy area behind the city wall. Under the emperor Caligula the area was drained and his mother Agrippina had a villa and garden built there. Later the emperor Nero decided to construct there a small circus (similar to the Coliseum), where not only games but also executions were conducted.
The apostle Peter was elected the first bishop of Rome in 43 A.D. And in 64 A.D., as a result of a large fire, 11 of 14 quarters of the city were almost completely burnt. The emperor Nero accused the Christians of arson and most of them were executed, including the apostle Peter. In 64 A.D. he was crucified at the circus of Nero and buried at the adjoining cemetery. The grave of the apostle Peter at once became a sacred place for the Christians of Rome. They decided that as soon as they could build a church in this place, its altar should be just above the grave of St. Peter.
The first basilica was erected above the grave of the apostle Peter under the emperor Constantine in 326 A.D., when Christianity became a legal religion of the Roman Empire. The basilica became one of the main sacred things of Christianity. All the Popes were crowned in the basilica, and in 800 A.D. even Charles the Great was declared emperor of the Holy Roman Empire there.
In the period of feudal disunity Rome, as well as large surrounding territories, belonged to the the Papal state. For several centuries the Pope was not only the spiritual head of the Catholics but also the ruler of a large state in the center of Italy.
In 19 century the separate principalities of Italy were united into a centralized state. The process of unification was completed in 1870 when Rome was included in the new united Italy and the Papal state ceased its existence. However, the Holy See demanded independence from Italy. And in 1929 Benito Mussolini granted independence to Vatican but its area was only 1.5 km2. The Basilica of St. Peter, as well as several papal palaces, are on the territory of Vatican. Some palaces house the most valuable collections of the Vatican museums.