The Saint Peter's Basilica has the largest interior of any Christian church in the world. It is regarded as one of the holiest Catholic sites.
The basilica is the burial site of its namesake Saint Peter, who was one of the twelve apostles of Jesus and the first Bishop of Rome.Historical evidence hold that Saint Peter's tomb is directly below the altar of the basilica.Many other Popes have been interred at St. Peter's since the Early Christian period.
It is cruciform in shape, with an elongated nave in the Latin cross form.The central space is dominated both externally and internally by one of the largest domes in the world.
The entrance is through a narthex, or entrance hall, which stretches across the building. One of the decorated bronze doors leading from the narthex is the Holy Door, only opened in Holy Years.
The nave which leads to the central dome is in three bays, with piers supporting a barrel-vault, the highest of any church. The nave is framed by wide aisles which have a number of chapels off them. There are also chapels surrounding the dome.
The four cherubs, two each side on the first piers of the nave, holds basin of Holy water. Each one is 2 meters in high.
At the heart of the basilica, beneath the high altar, is the Confessio or Chapel of the Confession, in reference to the confession of faith by St Peter, which lead to his martyrdom. Two curving staircases lead to this underground chapel at the level of the Constantinian church. Its marble steps are remnants of the old basilica and around its balustrade are 95 bronze lamps.
The baldacchino, a pavilion-like structure 30 metres (98 ft) tall and claimed to be the largest piece of bronze in the world. The concept was from the baldachin or canopy carried above the head of the pope in processions, and in part from eight ancient columns that had formed part of a screen in the old basilica. Their twisted barley-sugar shape had a special significance as the column to which Jesus was bound before his crucifixion was believed to be of that shape. They created four huge columns of bronze, twisted and decorated with olive leaves and bees, which were the emblem of Pope Urban.
According to Origen, Peter was crucified head downwards, by his own request because he considered himself unworthy to die in the same manner as Jesus. The crucifixion took place near an ancient Egyptian obelisk in the Circus of Nero. The obelisk now stands in Saint Peter's Square and is revered as a "witness" to Peter's death. It is one of several ancient Obelisks of Rome.
Around the basilica are: The Baptistery, the Chapel of the Presentation of the Virgin, the larger Choir Chapel, the Clementine Chapel with the altar of St Gregory, the Sacristy Entrance, the left transept with altars to the Crucifixion of St Peter, St Joseph and St Thomas, the altar of the Sacred Heart, the Chapel of the Madonna of Colonna, the altar of St Peter and the Paralytic, the apse with St Peter's Cathedra, the altar of St Peter raising Tabitha, the altar of the Archangel Michael, the altar of the Navicella, the right transept with altars of St Erasmus, Saints Processo and Martiniano, and St Wenceslas, the altar of St Basil, the Gregorian Chapel with the altar of the Madonna of Succour, the larger Chapel of the Holy Sacrament, the Chapel of St Sebastian and the Chapel of the Piet, and Chapel of Blessed John Paul II.
The Basilica of St. Peter is one of four Papal Basilicas or Major Basilicas of Rome the others being the Basilica of St. John Lateran, Santa Maria Maggiore and St. Paul outside the Walls. It is the most prominent building in the Vatican City. Its dome is a dominant feature of the skyline of Rome.
The Chair of Saint Peter is a relic conserved in St. Peter's Basilica, enclosed in a gilt bronze casing that was designed by Gian Lorenzo Bernini and executed 1647-53.
There are over 100 tombs within St. Peter's Basilica (extant to various extents), many located in the Vatican grotto, beneath the Basilica. These include 91 popes, St. Ignatius of Antioch, Holy Roman Emperor Otto II, and the composer Giovanni Pierluigi da Palestrina. Exiled Catholic British royalty James Francis Edward Stuart and his two sons, Charles Edward Stuart and Henry Benedict Stuart, are buried here, having been granted asylum by Pope Clement XI. Also buried here are Maria Clementina Sobieska, wife of James Francis Edward Stuart, Queen Christina of Sweden, who abdicated her throne in order to convert to Catholicism, and Countess Matilda of Tuscany, supporter of the Papacy during the Investiture Controversy. The most recent interment was Pope John Paul II, on 8 April 2005.Later the remains were moved inside the basilica.