St. Peter's Basilica, located in Vatican City, is a massive church known for its Renaissance architecture and iconic dome that towers over Rome's skyline. Built to replace the old St. Peter's Basilica, construction started in 1506 and was completed in 1626. Designed by famous architects like Bramante, Michelangelo, and Carlo Maderno, the basilica is a major pilgrimage site and holds historical significance as the burial place of Saint Peter. With its grandeur and religious importance, St. Peter's Basilica is considered one of the greatest churches in the world.