Unexcused absences create staff shortages at Alabama's Holman Correctional Facility.

The violent history of San Quentin State Prison in California.

Grantt Culliver controls the disruptive inmates of Holman Correctional Facility.

Dangerous inmates are segregated from the rest of the prison population.

A 20-year-old inmate speaks about how he grew up on the streets and what motivates him to turn his life around.

Correctional officers search prisoners for weapons.

A dangerous combination of gangs, drugs and boredom encourages inmates to commit violent offenses in prison.

The prison's annual poetry slam.

Relationships both inside and outside the prison walls.

Inmates receive visitors during their prison stays.

Serving life sentences or death sentences in prison.

Inmates at San Quentin State Prison find ways to fight boredom.