A Small Altar in Lower Room of Mamertime Prison
A small altar in the lower room of the Mamertime Prison. The upside-down cross lends the desolate place an extra-sinister air, but that's just the Cross of St. Peter (who was crucified upside down). In the foreground is a spring that Peter is said to have made miraculously spring up so he could baptize his fellow prisoners; the altar relief shows him doing so.
Credit: Holly Hayes