The vatican city
Vatican City is the smallest city-state in the world, with only 880 people, but is one of the most visited. This is mainly because it is in the middle of Rome and the 14.4 acres are packed with some of the world's most beautiful churches and museums.
Although Vatican City is an independent country, it is completely surrounded by the city of Rome. This center of Roman Catholicism is a must-see. It is bounded by the Tiber River and stretches west (about 1 200 m long and 800 m at its widest point).
Crossing from the city of Rome over the Tiber, the first building you see, at the end of Via della Conciliazione, is St. Peter’s Basilica (Michelangelo designed the dome and his Pieta is exhibited within).
Plan at least 3 (or more) hours in St. Peter’s: After walking around inside be sure to go to the roof for the view (it’s usually hazy so you might just want to go up there for the pretty sunsets) visit its in-house museum and see the grotto below (where St. Peter and John Paul II, among other popes, are buried). The baldequino over the main altar built with bronze looted from the Pantheon is an interesting example of baroque design.