Vatican City

Vatican City, officially the Vatican City State, is the Holy See's independent city state, an enclave within Rome, Italy. The Vatican City State, also known as The Vatican, became independent from Italy with the Lateran Treaty (1929), and it is a distinct territory under "full ownership, exclusive dominion, and sovereign authority and jurisdiction" of the Holy See, itself a sovereign entity of international law, which maintains the city state's temporal, diplomatic, and spiritual independence. With an area of 49 hectares (121 acres) and a population of about 825, it is the smallest sovereign state in the world by both area and population.
Source: Wikipedia.