St. Peter's Basilica
As the focal point of the Catholic Church, St. Peter's Basilica is the most popular attraction in all of Rome. Situated at the heart of Vatican City, the origins of the basilica come from the construction of a church on the site of St. Peter's grave in 349 A.D. The original basilica began to fall into disrepair by the 15th century, prompting Pope Nicolas V to order the construction of a new facility.