Construction workers pour concrete at 1 a.m. in Chandler, Ariz. Sarah Ventre/KJZZ hide caption

Found in Botswana, the Lesedi la Rona diamond is up for auction and valued at $70 million. Seth Wenig/AP hide caption

Moraine Park is a grassy valley inside Rocky Mountain National Park. Wes Lindamood/NPR hide caption

Colombian President Juan Manuel Santos (left) and FARC commander Timoleon Jimenez (right) shake hands as Raul Castro looks on at a signing ceremony of a cease-fire deal in Havana last Thursday. "It is the first time ever that a guerrilla group lays down its arms to submit to a justice system where they are going to be investigated, judged, and condemned and sanctioned," Santos told NPR. Desmond Boylan/AP hide caption

Kurt Britz checks a driver's license at the 3-D Denver Discrete Dispensary on Jan. 1, 2014, the first day recreational marijuana sales were legal in Colorado. Possession remains illegal for those under 21 years old, and statistics show a widening racial gap in arrests for those offenses. Theo Stroomer/Getty Images hide caption