World's Most Dangerous Prisoners

At 6ft 7, Gary Vinter is a convicted double murderer and one of the most feared men in the prison system. He stabbed a fellow inmate in the eye and gave another brain damage.

Following the crimes and incarceration of James 'Porky' O'Rourke's, including when he committed murder at age 22 by dropping a slab of concrete on a mans head. The episode documents his time in prison, such as his attacks on prison officers, stabbing the governor in the exercise yard and strangling a fellow inmate.

Exploring the life and convictions of Joanne Dennehy. After serving a short sentence in Peterborough prison, she committed a frenzied knife attack on a man she lured back to her apartment with the promise of sex. Whilst on the run from police, Dennehy proceeded to violently stab and murder two more men over the next 10 days, before stabbing two men out walking their dogs.

Mark Hobson is a man with an extreme propensity for violence; a notorious British spree killer who murdered twin sisters, as well as an elderly couple in their own home.

Following the crimes of Jaime Osuna, such as the metal and physical abuse he inflicted on his ex-wife, as well as the torture and murder of a mother of six who resembled his ex-partner. Awaiting trial, he began practicing Satanism and attempted to kill a fellow inmate.

Edward Johnson is a cold, calculating killer who brutally murdered a female friend. Once behind bars for his heinous crime, the violence continued when he killed a correctional officer with a hammer.

James Robertson is one of the most feared men in the US prison system. He murdered his cellmate and attacked a correctional officer to get his wish - to be put on death row.

At the age of 18, Christa Gail Pike became one of the youngest women in the US ever to be sent to death row. Pike, a satanist, murdered of a young woman keeping a piece of her victim's skull as a trophy.

Tyler Davis Bingham started out as a petty criminal but ended up leader of the white supremacist gang, The Aryan Brotherhood. When engaged in a fight, he would never allow anyone to live.

Freddy Geas was a hired hitman for the Italian-American Mafia,and he got away with murder for years. Eventually the mobster did get caught. He allegedly beat the notorious Boston Mob boss Whitey Bulger to death, while behind bars.