This is the prison where Peter and Paul were held before they were martyred. It overlooks the Forum Romanum and the Colosseum.
The altar above the prison cell below.
In Peter and Paul's day, this was the only way into and out of the prison cell below.
This staircase was not installed until the 13th (?) century.
The altar in the prison cell beneath.
Total dimensions of the cell: a cylindrical space approximately 20-30 ft. in diameter and approximately 7 ft. high. More often than not, this space was packed full of people.
This was the latrine area.