The Latin word basilica (derived from Greekβασιλική στοά, Royal Stoa, the tribunal chamber of a king), has three distinct applications in modern English. The word was originally used to describe a Roman public building, usually located in the forum of a Roman town. By extension it was applied to Christian buildings of the same form and continues to be used in an architectural sense to describe those buildings with a central nave and aisles. Later, the term came to refer specifically to a large and important church that has been given special ceremonial rights by the Pope.
Catholic Basilicas are Catholic pilgrimage sites, receiving tens of millions of visitors per year. In December 2009 the Basilica of Our Lady of Guadalupe set a new record with 6.1 million pilgrims during Friday and Saturday for the anniversary of Our Lady of Guadalupe.
St. Peter's Basilica (Latin: Basilica Sancti Petri), officially known in Italian as Basilica di San Pietro in Vaticano or Basilica Papale di San Pietro, is a Late Renaissance church located within Vatican City.
In Roman Catholic tradition, the basilica is the burial site of its namesake Saint Peter, one of the twelve apostles of Jesus and, also according to tradition, the first Bishop of Rome and therefore first in the line of the papal succession. Tradition and some historical evidence hold that Saint Peter's tomb is directly below the altar of the basilica. For this reason, many Popes have been interred at St. Peter's since the Early Christian period. There has been a church on this site since the time of Constantine. Construction of the present basilica, replacing the Old St. Peter's Basilica of the 4th century, began on 18 April 1506 and was completed on 18 November 1626.