Deadman Wonderland is place in the anime and manga series with the same name. It is a theme park that is also a prison.
Unlike regular prisons, Deadman Wonderland forces prisoners to work and go through deadly obstacle games, which is viewed by an audience who are enjoyed by the death because of them being criminals.
It's true purpose is to find prisoners who are called deadmen, a person who has the Branch of Sin to use there blood as weapons, and to make them fight. The deadman that loses has to have a body part removed.