History of the Vatican

History of the Vatican
The Vatican, a European microstate, is located in the western, central part of Rome on Vatican Hill, several hundred metres west of the Tiber River. It is the smallest sovereign state in the world, totalling only 0.44 square kilometres or 110 acres of land. All 3.2 kilometres of the Vatican’s limits border Italy and closely follow the wall surrounding the city, which was constructed to protect the pope from outside attack. The Vatican is also the first and only country that is carbon neutral, meaning its net carbon emissions total zero. It achieved this by planting the Vatican Climate Forest in Hungary.
In the early first century, Julia Vispannia Agrippina, granddaughter of the first Roman emperor Gaius Julius Caesar Augustus, had an elaborate garden built in an uninhabited area separated from Rome by the Tiber. After the death of Agrippina, her son, Gaius Julius Caesar Augustus Germanicus (more commonly known as Caligula) began the construction of a circus on the site of her gardens. Nero Claudius Caesar Augustus Germanicus (more commonly known as Nero) completed the circus after the death of Caligula. The Circus of Nero became the site of martyrdom for many Christians and it is believed that it was the site where Saint Peter was crucified upside down.
In 1870, after a nominal resistance from papacy forces, the Piedmont forces, which had united the rest of Italy, annexed Rome. The pope at this time was Pope Pius IX (1846-1878) and his fate, as well as the fate of the papacy, became known as the Roman Question from 1861 until 1929. The popes were undisturbed in their palace and were given certain freedoms under the Law of Guarantees, including the ability to send and receive ambassadors who were given full diplomatic immunity. Many citizens of the Kingdom of Italy continued to recognize the Holy See as the sovereign entity over the Papal States. Although Italy had guaranteed not to interfere with the Holy See inside the Vatican...