The interior, which includes 45 altars, is decorated by many famous artists. Some of the most important works in the church are the Pieta by Michelangelo, the papal altar by Bernini, the Throne of St. Peter – also by Bernini – and the Monument to the Stuarts by Canova. The opulent interior can be visited daily for free although a strict dress code is enforced.

The Dome

There is a widespread assumption that the dome, or cupola, as it presently stands, was designed by Michelangelo, who became chief architect in 1546. In fact, Michelangelo’s design called for a spherical dome. At the time of his death (1564), only the drum, the base on which a dome rests, had been completed. The dome proper was redesigned and vaulted, between 1585 and 1590, by the architect Giacomo della Porta, with the assistance of Domenico Fontana, who was probably the best engineer of the day. Fontana built the lantern the following year, and the ball was placed in 1593.

As built, the double dome is brick, 42.3 metres (138.8 ft) in interior diameter (almost as large as the Pantheon), rising to 120 metres (394 ft) above the floor. In the mid-18th century, cracks appeared in the dome, so four iron chains were installed between the two shells to bind it, like the rings that keep a barrel from bursting. (Visitors who climb the spiral stairs between the dome shells can glimpse them.) The four piers of the crossing that support it are each 18 metres (59 ft) across. It is not simply its vast scale (136.57 m or 448.06 ft) from the floor of the church to the top of the added cross) that makes it extraordinary. Della Porta’s dome is not a hemisphere, but a paraboloid: it has a vertical thrust, which is made more emphatic by the bold ribbing that springs from the paired Corinthian columns, which appear to be part of the drum, but which stand away from it like buttresses, to absorb the outward thrust of the dome’s weight. The grand arched openings just visible in the illustration but normally invisible to viewers below, enable access (but not to the public) all around the base of the drum; they are dwarfed by the monumental scale of their surroundings. Above, the vaulted dome rises to Fontana’s two-stage lantern, capped with a spire.

The Burials

Basilica of Saint Peter Is Burial site of St Peter. There are over 100 tombs located within St. Peter’s Basilica. These include 91 popes, St. Ignatius of Antioch, and the Renaissance composer Giovanni Pierluigi da Palestrina. James Francis Edward Stuart and his two sons Charles Edward Stuart and Henry Benedict Stuart were exiled, Catholic English royalty who are buried here after being granted asylum by Pope Clement XI. The most prominent woman entombed is Christina of Sweden, who abdicated her throne in order to convert to Catholicism. The most recent interment was Pope John Paul II on April 8 2005.

The Swiss Guards

Near the entrance of the Basilica you will probably encounter some of the famous Swiss guards. Since 1506 when pope Julius II invited Helvetian soldiers to join the small Vatican army, they have been the guards of the Vatican and the pope in particular. All entrants to the army must be Swiss, catholic and they must take the oath of loyalty to the pope. This oath is taken May 26th, to commemorate the sacking of Rome on the same day in 1527 when Swiss guards protected pope Clement VII during his escape to the Castel Sant’Angelo. Of the 189 guards, only 42 survived.

Google Earth Placemark – The Basilica of Saint Peter inside Vatican City.