An estimated 80,000 Americans are in solitary confinement - even people who haven't committed violent crimes - sometimes for years, or even decades. Using extraordinary access to the segregation unit at the maximum security Maine State Prison, FRONTLINE examines America's use of solitary confinement - a practice U.S. prisons and jails resort to more than most other countries. Some prison officials see it as necessary to keep order and safety, but critics say it is inhumane and counterproductive. "Solitary Nation" is an extraordinarily rare and intimate view of life in solitary, through the stories of inmates living in isolation, the prison officers who keep them locked in, and a new warden who is re-thinking the practice and trying to reduce the number of inmates in solitary.