St. Peter's Basilica, one of the four papal or major basilicas in Rome, is the largest church in the Catholic world. It is neither the official seat of the pope, nor the first basilica of Rome, nor the parish of Vatican City, but it is the main papal church. It is where most of the papal ceremonies are held. Nor is it the Cathedral of Rome, as it is the Archbasilica of St. John Lateran, the first basilica of Rome.
Its construction, begun by decision of Pope Julius II, started in 1506 on the site of the ancient Constantinian basilica and was completed in 1626. Several architects were involved in its construction, including Donato Bramante (the project's first architect), Michelangelo and Gian Lorenzo Bernini (also the architect of St. Peter's Square, whose famous colonnade is the border between Italy and Vatican City).
According to Christian tradition and historical and scientific evidence, the tomb of St. Peter is under the high altar of the basilica. Also most of the popes have been buried in St. Peter's since early Christian times.
St. Peter's Basilica is one of the most sacred places in Catholicism, as well as being of unparalleled beauty.
