The 372-bed Bill Clayton Detention Center is a medium-security prison that is currently sitting empty in Littlefield, Texas. John Burnett/NPR hide caption

itoggle caption John Burnett/NPR

Families of youth incarcerated at the Walnut Grove Youth Correctional Facility in Mississippi listen to testimony at a hearing about alleged inmate abuse. Phoebe Ferguson for NPR hide caption

itoggle caption Phoebe Ferguson for NPR

Sgt. Nathan Scheller was twice denied for a Purple Heart, though roadside bomb explosions left him with lasting cognitive damage. Above, Scheller walks with his wife, Miriam, and his family. NPR/Frontline hide caption

itoggle caption NPR/Frontline

Avon Twitty was recently released from a halfway house in Washington, D.C., after serving three years in the Communications Management Unit at the Terre Haute, Ind., prison. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Inside the Terre Haute federal prison, the Communications Management Unit houses inmates convicted of or suspected of terrorism. Michael Conroy/AP hide caption

itoggle caption Michael Conroy/AP

A simulated Canadair Regional Jet flight deck at Embry-Riddle Aeronautical University in Daytona Beach, Fla. Robert Benincasa/NPR hide caption

itoggle caption Robert Benincasa/NPR