photo 33 of 126
St. Peter's Basilica: St. Peter's Basilica

St. Peter's Basilica

The original church was built by Constantine in 324, but the present building is a Renaissance reconstruction of 1506-15. Until recently the largest church in the world, St. Peter's remains one of the holiest sites in Christendom. It stands over the traditional site of Saint Peter's burial; his tomb is under the main altar.

Credit: Holly Hayes