Sgt. Victor Medina suffered brain damage in 2009 when a roadside bomb exploded in Iraq. Blake Gordon/Aurora Photos hide caption

itoggle caption Blake Gordon/Aurora Photos

Josh Apsey, then an 18-year-old lance corporal, bumps fists with his dad through a bus window as he begins his trip to Afghanistan in 2009. Apsey is still in the Marines, serving in Virginia, and says the war in Afghanistan made him a different person. John W. Poole/NPR hide caption

itoggle caption John W. Poole/NPR

Drone pilots fight a war from the safety of bases in the U.S. but confront some of the same wartime stresses as their comrades on the battlefield. Damian Dovarganes/AP hide caption

itoggle caption Damian Dovarganes/AP