Worshippers congregate for the Pope’s weekly mass at St. Peter’s Basilica in the early morning hours. St. Peter’s Basilica was begun by Pope Julius II in 1506 and completed in 1615 under Paul V. The building is “the church of the popes” and is a major pilgrimage site. The Basilica is decorated with detailed mosaics, gilding, coffered ceilings and works by Bernini and Michelangelo. It is illuminated with strategically placed windows which produce dramatic shafts of light throughout the day. St. Peters Basilica is the heart of the Vatican and the Holy See.