Afghan security personnel inspect a damaged bus at the site of a suicide attack in Kabul, Afghanistan, on Saturday. There was no immediate report of casualties, but the attack was one of several in the last 24 hours that have been blamed on the Taliban. Rahmat Gul/AP hide caption

itoggle caption Rahmat Gul/AP

At about $15 a gram, saffron is the world's most expensive spice. Rumi Spice has a unique model of employing Afghan farmers who are growing it that aims to double or even triple their annual income. Cristina Hirschkorn/Courtesy of Rumi Spice hide caption

itoggle caption Cristina Hirschkorn/Courtesy of Rumi Spice

Retired 1st Sgt. Keith Melick (right) and retired Army Special Forces Command Sgt. Maj. Roy Wilkins met when Melick, a medic, treated Wilkins after an IED explosion. They were reunited nearly 10 years later. StoryCorps hide caption

itoggle caption StoryCorps

U.S. soldiers stand at a checkpoint around Lakokhel camp in Afghanistan in 2010. Many soldiers return from war suffering from "moral injuries," or dealing with the fact that their sense of right and wrong was violated. Martin Bureau/AFP/Getty Images hide caption

itoggle caption Martin Bureau/AFP/Getty Images

Gen. John F. Campbell, the top U.S. commander in Afghanistan, speaks during a ceremony in Kabul on Aug. 26. Campbell is overseeing the U.S. drawdown in the country after 13 years of war. Massoud Hossaini/AP hide caption

itoggle caption Massoud Hossaini/AP