President Obama is the first sitting president to visit a federal prison. Kevin Lamarque/Landov hide caption

A cell block at the now-closed Abu Ghraib prison in Baghdad, a facility notorious for photos released in 2004 showing U.S. soldiers torturing and humiliating inmates. Karim Kadim/AP hide caption

Known by the nickname "Wall Street," Curtis Carroll teaches financial literacy at the San Quentin Prison, helping inmates prepare for life after incarceration. Carroll, however, is serving a life sentence. Courtesy of The California Department of Corrections and Rehabilitation hide caption

Latandra Ellington, 36, was serving time for tax fraud at Lowell Correctional Institution when she died. Florida Department of Corrections hide caption

A Los Angeles County Department of Public Health worker shows condoms for weekly distribution to inmates in the Men's Central Jail. George Lavender hide caption

The Lafayette Parish Correctional Center in downtown Lafayette, La. By most counts, Louisiana has the highest incarceration rate in the country, but sentencing reformers have loosened some of the state's mandatory minimum sentences and made parole slightly easier to get. Denny Culbert for NPR hide caption