St. Peter's Basilica from the River Tiber.
By Roman Catholic tradition, the basilica is the burial site of Saint Peter, one of the twelve apostles of Jesus.
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St. Peter's is famous as a place of pilgrimage, where the Pope presides over several ceremonial functions. As a work of architecture, it is regarded as the greatest building of its age. St. Peter's holds the rank of Major Basilica and it is not a cathedral.