The Vatican Grottoes are a necropolis that extends beneath a portion of the nave of St. Peter's Basilica in Vatican City, three meters below the current level, from the main altar to about halfway down the nave.

Although erroneously called "caves," the Vatican grottoes reflect the difference between the old Constantinian basilica and the current basilica, as they do not extend the entire length of the nave of the current basilica, as the original building only encompassed a certain percentage of what is now St. Peter's.

The Vatican grottoes branch out into niches, aisles, and chapels, resembling a three-aisled church (an area called the "old grottoes"), with chapels housing the tombs of the popes; the semicircular apse of the church, with chapels and funerary monuments (an area called the "new grottoes"), which is immediately beneath the papal altar and Michelangelo's dome; and the underground necropolis, the tomb of the Apostle Peter, the first pope of the Catholic Church.

The Vatican grottoes are an impressive monument to varied historical memories. In addition to being the resting place of several popes, the grottoes are filled with works of art from the ancient basilica.^[1]

Being buried in the Vatican grottoes, near the tomb of Saint Peter, was the wish of many popes, kings, and queens, just as it was for the early Christians.

Some of the earliest people to be buried in the grottoes are the German Pope Gregory V; Emperor Otto II; Adrian IV, the only English pope in history; Boniface VIII, who proclaimed the first Holy Year in 1300 and rests beneath the sculpture by Arnolfo di Cambio; and Pius VI, whose body is in an early Christian sarcophagus, separate from the remarkable sculpture of him by Antonio Canova.

Among the kings are James III and his sons, as well as Queen Christina of Sweden, next to the former niche of John Paul II, across from the Confession crypt.^[2]

Pope Pius XI strongly desired to be buried "as close as possible to Peter," so his successor, Pius XII, ordered a broad archaeological campaign around Peter's tomb to establish the authenticity of the site.

From 1940, excavations were organized to search for St. Peter's tomb, and they were carried out in secret for ten years, even during World War II. Inside the tomb, archaeologists found a small ossuary with Greek inscriptions, interpreted as "Peter is here", which gave them confidence that this was the location.

Pope Pius XII made the official announcement, via radio, in the Holy Year of 1950. The fortunate discovery of some bones of a 60-70-year-old man, wrapped in a precious purple cloth woven with gold threads, and the trust of the site, led Paul VI to believe that they were the remains of St. Peter's body.

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