Artist and flipbooked.com founder Liza Tudor thumbs through "1st Steps," a flipbook of Nicole Garrens' son Zander's first steps. Tudor sent the flipbook to Garrens' husband, Roy, who's currently incarcerated in Texas. Noel Black for NPR hide caption

President Obama arrives at the White House on Monday, after a trip to Walter Reed National Military Medical Center in Bethesda, Md. Obama wrote an op-ed in Monday's Washington Post announcing new limits on the use of solitary confinement in federal prisons. Carolyn Kaster/AP hide caption

Ali Rezaian, brother of Washington Post Tehran Bureau Chief Jason Rezaian (shown in picture frame), talks about his brother's imprisonment in Iran while testifying before the House Foreign Affairs Committee on June 2, 2015. Iranian media outlets are reporting that Rezaian has been released. Chip Somodevilla/Getty Images hide caption

Supporters of Venezuelan opposition leader Leopoldo Lopez shout "Freedom for Leopoldo" outside a court in Caracas in September. Lopez, Venezuela's best known political prisoner, was arrested and sentenced to nearly 14 years in prison after giving a speech at a demonstration last year. Fernando Llano/AP hide caption

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