The Papal Basilica of Saint Peter, officially known in Italian as Basilica Papale di San Pietro in Vaticano and commonly known as Saint Peter’s Basilica, is a Late Renaissance church located within the Vatican City. Saint Peter’s Cathedral has the largest interior of any Christian church in the world. It`s an impressive building, especially at night when it`s light up. Make sure to pay a visit during the day to admire the interior, the entrance is free. Going early in the morning or at the end of the day will prevent you from having to wait in long lines. Check out more places to visit in Rome.