The World's Worst Prisons. Inside Stories from the most Dangerous Jails on Earth: Farrington, Fitzgerald

In some of the world's harshest prisons, from Alcatraz to Pollsmoor, an unending battle rages between convicts and warders.

Inside the prison walls, gangs rule, guards devise sadistic punishments, and newcomers suffer abuse at the hands of experienced tormentors.

From overcrowding in Nairobi to drug smuggling in Sao Paolo to the harsh labour camps of North Korea, The World's Worst Prisons reveals what life behind bars is really like.