New St Peter's Basilica in Vatican City, Rome underwent major reconstruction in the 16th century after the old basilica fell into disrepair. Led by architects like Bramante, Michelangelo, Maderno, and Bernini over more than 100 years, the new basilica was built in Renaissance and Baroque styles. Its massive dome, supported by thick piers and vaults, towers over the nave, transepts, and apse. The basilica's lavish interior houses artwork like Michelangelo's Pietà and Bernini's papal altar. Its large square and colonnades make it a focal point in Rome.