The U.S. is the world leader in solitary confinement, with more than 80,000 prisoners being held in isolation. But in recent years, more than 30 states have begun to experiment with reforms aimed at reducing the use of solitary. On Tuesday, April 18,... (more) FRONTLINE presents “Last Days of Solitary” — a searing, two-hour exploration of this controversial practice. Filmed over three years, “Last Days of Solitary” goes inside one state’s ambitious attempt to decrease its use of solitary and investigates what happens when prisoners who have spent considerable time in isolation try to integrate back into society.