If you looked at Vatican City on a map, you would likely think it was part of the city of Rome. Geographically, it seems to be, but legally speaking the 110-acre, walled-in site is a sovereign city-state. In fact, it is the smallest independent state in the world. This is the place the pope calls home, the location of St. Peter's Basilica, and the site of the Sistine Chapel. Even if you are not Catholic (or not religious at all), the sheer grandeur of Vatican City and the treasured artworks inside its buildings can make for a fascinating day of touring.