Mariama and Fomba Kanneh play in an open space in Barkedu, Liberia. With schools closed across the country, many kids spend their time playing outside every day. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

Education experts faced off on the motion "Embrace the Common Core" at an Intelligence Squared U.S. debate, moderated by John Donvan (center). Samuel LaHoz/Intelligence Squared U.S. hide caption

itoggle caption Samuel LaHoz/Intelligence Squared U.S.

About 40 percent of high schools start before 8 a.m., which contributes to chronic sleep deprivation among teens, according to the American Academy of Pediatrics. Chris Waits/Flickr hide caption

itoggle caption Chris Waits/Flickr

Inmates from several Alabama state prisons take a math class at J.F. Ingram State Technical College. The campus becomes a medium-security facility when the students arrive. Dan Carsen/WBHM hide caption

itoggle caption Dan Carsen/WBHM

Teachers with the Jennings School District pick up trash Tuesday on West Florissant Avenue in Ferguson, Mo., the scene of nightly police clashes. Jennings and the neighboring Ferguson school district have canceled class due to ongoing unrest. Elise Hu/NPR hide caption

itoggle caption Elise Hu/NPR