The central church of Roman Catholicism, Saint Peter’s Basilica in the Vatican City (State of the Vatican City) stands on the site where Saint Peter is believed to have been buried. Built in the 16th and 17th centuries to replace an earlier church, it is the largest house of worship in the world, with space to accommodate 50,000 people. Its original overall outline was that of a Greek cross, but it is now shaped like a Latin cross. Saint Peter’s has been used for papal ceremonies since 1870.

The construction of Saint Peter’s Basilica in Rome began in 1506 and spanned more than a century. Many popes sponsored its construction, and many architects contributed to its design. Among the latter was Michelangelo, chief architect from 1546 until his death 18 years later. Saint Peter’s is filled with artistic treasures and is called the "Church of the Popes".