The crypt is accessible by a central staircase. The archbishop Natale Bruni is buried in the first chapel on the left, a medallion with his visage was completed by Giuseppe Graziosi. The altar on the right is dedicated to the "Madonna of Lourdes" and was carved by the sculptor Vigni of Florence. The main altar has a ciborium in part work of the brothers Pedrazzi. To the left of the entrance is the baptistery, the bronze statue of "St John the Baptist" was sculpted by Graziosi. To the left is a chapel dedicated to those fallen during the Conquest of Ethiopia (1935-37). The "Pietà" in terracotta was sculpted by Manfredini.