The Vatican
Vatican City is an independent state with a population of roughly 1000 people, who are principally Vatican employees, including a large number of priests and nuns.
The pope is the monarch for life of the Vatican. The state is administered by a seven member commission appointed by the pope.
The state's revenues are derived from international donations and numerous international investments. The Vatican's Institute for Religious Works, commonly known as the Bank of the Vatican, has reserves exceeding US $11 billion. The institute has interests in a large range of other banks and owns a vast amount of real estate internationally.
Despite a number of books about the Vatican's financial dealings and the Bank of the Vatican's involvement in a scandal around the bankruptcy of the Ambrosiano Bank, its financial affairs are largely secret.