A stabbing puts the prison on high alert; a brash new inmate gets taken down a notch.

An anonymous tip puts Internal Affairs on high alert.

The many meanings of 'cutting' at Indiana State Prison.

Contraband finds its way to the inmates.

The Residential Treatment Unit.

Some prisoners resort to violence while others become victims.

While visiting Limon Correctional, the Lockup crew is greeted by angry inmates and the cell extraction team is called in to help.

Behind the walls of six maximum-security prison in Serbia, Poland, and the Czech Republic.

Life inside prisons throughout Scotland and Belgium.

Extractions at Colorado State Penitentiary.

Violence at the Limon Correctional Facility in Colorado.