St Peter's Basilica and the Sistine Chapel

St Peter's Basilica, completed in 1626 after more than a century of construction under a succession of architects including Bramante, Michelangelo, and Bernini, stands on ground traditionally identified as the burial site of the apostle Peter and remains the largest church building in the world by interior volume, functioning as the ceremonial center of the papacy for major liturgies, papal elections' public announcements, and the veneration of Peter's traditional tomb beneath its high altar. Michelangelo's dome, an engineering achievement in its own era, dominates the Rome skyline and became a model widely imitated in later church architecture across the Catholic world, while Bernini's bronze baldachin over the high altar and his sweeping colonnade enclosing St Peter's Square shaped how the building presents itself to pilgrims arriving from every direction.

The nearby Sistine Chapel, built under Pope Sixtus IV in the 1470s and famous chiefly for Michelangelo's ceiling frescoes completed between 1508 and 1512 and his later Last Judgment on the altar wall, serves a specific institutional function beyond its fame as an artwork: it is the chapel in which the College of Cardinals meets in conclave to elect a new pope, sealed off from outside contact until white smoke signals a decision has been reached. The chapel's side walls also carry an earlier fifteenth century fresco cycle by artists including Botticelli and Perugino depicting parallel scenes from the lives of Moses and Christ, a program less famous than Michelangelo's ceiling but integral to the chapel's original theological design.