Prison

New York City's infamous jail, Rikers Island, currently houses nearly 7,000 detainees. Chefs, not inmates, do the cooking. But while they're on their shift, the chefs are locked in, too. There are cameras everywhere, monitored from the guard's office. Knives are chained to heavy machinery.

Eric King served almost two years at the federal super-maximum security prison ADX Florence in Colorado.

Mohamedou Ould Slahi was imprisoned without charge at Guantanamo Bay for nearly 15 years.

Ould Slahi speaks to Business Insider about the prison layout, the facilities, the food, and yard time. He reveals what torture methods were used and how guards interacted with detained people.