The Vatican Grottoes, built between 1590 and 1591, were originally designed to support the weight of St. Peter’s Basilica above. What started as underground vaults quickly became a sacred space, especially after Pope Clement VIII renovated part of the crypt in 1592 and created the Clementine Chapel, which now houses St. Peter's tomb.
Architecturally, the Grottoes mix solid, sturdy construction with beauty, featuring vaulted ceilings and intricate chapels. Pope Paul V expanded them in the early 17th century, adding corridors and new spaces for prayer. Renowned architect Gian Lorenzo Bernini helped design many of the chapels, blending elegance with simplicity.
Today, the Grottoes house the tombs of Popes, saints, and other important figures. Visitors can also see relics from the original 4th-century basilica, all connected to the ancient Vatican Necropolis below.