Holly See
The Uninhabited Realm: Unveiling the Secrets of the Holy See
The Holy See is the only country in the world that has no residents.
Vatican City Post Office
Within the Vatican City, there is a post office that has an unusual privilege - it is the only post office in the world that does not bear any country's name on its postage stamps.
Vatican Observatory
The Vatican has its own observatory, known as the Vatican Observatory, where a team of Jesuit astronomers conducts cutting-edge research, exploring the cosmos and bridging the gap between science and faith.