A few months ago I visited Kilmainham Gaol or The Jail of Kilmainham located in Dublin. I will leave the photos speak by themselves.
People on the death row would go to the church to receive their last blessings and then cross the door behind the altar to go thank the blesser.
The door in the middle leads directly to the altar shown before. They hanged inmates right by the balcony and let them there for a few days to serve as a deterrent.