Vatican Grottoes

They can be reached by a stairway off the left aisle of the Basilica and are about three meters under the floor of the part of the Church that was built in the 1500s. Wrongly called “grottoes”,  they occupy the space of the Basilica built by Constantine in the IV Century, though raised a bit higher actually. It is composed of three aisles with chapels on the sides in which are funeral monuments for numerous popes and numerous works of art that decorated the old Saint Peter's, destroyed to make way for the new one.