6The Vatican: Swiss guards keep watch as pilgrims file past St Peter's basilica to pray at the coffin of the late pope John Paul II following his beatification Photograph: Filippo Monteforte/AFP

However, Saint Peter's Basilica, which is located in Vatican, is the largest cathedral in the world.

Being the creator for three of the world's greatest icons: the statue of David, the painted ceiling of the Sistine Chapel in Vatican and the dome of St.