This photo shows St. Peter's square with the front facade of Saint Peter's in Rome. The square can hold 400,000 people. In the foreground is an Egyptian obelisk which was transported to the square from the ruins of Nero's Circus. The largest church in the world, St. Peter's is a basilica (a famous and important church) but it is not a cathedral (the church of a bishop). Begun in 1506, the present basilica was not completed until 1626. It is the third church built on this location. The original St. Peter's was built in 319 by the Emperor Constantine over the site of the tomb of St. Peter. Due to its deteriorating condition, reconstruction of this original church was begun in 1452 but was abandoned due to lack of funds. In addition to its size, Saint Peter's Basilica is famous for many art works inside, including Michelangelo's famous statue the "Pieta".