St. Peter's Dome, Dome of St. Peter's Basilica in Vatican City

The Dome is a structure in Vatican City that rises above the main altar of the basilica with a double-shell construction of brick and travertine. The inner shell displays mosaics with religious figures, while the outer shell is covered with lead panels and crowned by a lantern with columns.

Pope Julius II ordered the rebuilding of St. Peter's in the early 16th century, and Donato Bramante's design placed a hemispherical dome over a Greek-cross plan; the first stone was laid on 18 April 1506. Michelangelo took over in 1546 and worked on the dome until his death in 1564, leaving a wooden model. Giacomo della Porta and Domenico Fontana completed it in 1593 under Clement VIII, raising the curve and adding chains to resist lateral thrust.

Romans call the dome "il Cupolone", a nickname in the local dialect. The four colossal pillars supporting it each enclose a space comparable to an entire church, and in the niches at floor level stand marble statues of Saint Veronica, Saint Helena, Saint Andrew and Saint Longinus, the last carved by Bernini.

Access is through a narrow spiral staircase inside the basilica that leads visitors upward through several levels. Wait times are shorter in the morning, and the final sections require physical effort through narrow passages between the two shell walls.

The lantern at the top weighs around 800 tons and rests on a framework of iron chains that distribute the load onto the main vault. From the platform beneath the lantern, visitors can see the entire church below and recognize the symmetry of the elliptical plaza.