A training session for instructors who teach hand-to-hand combat, or combatives, at the Fort Benning military base in Georgia. Pouya Dianat for NPR hide caption

itoggle caption Pouya Dianat for NPR

In 2010 US Army veteran Jeff Barillaro returned from Iraq with severe PTSD. Since then Barillaro, whose stage name is "Solider Hard," has been rapping about his struggles and performing for troops, veterans, and military families across the US. Erik M. Lunsford/NPR hide caption

itoggle caption Erik M. Lunsford/NPR

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

Heirloom beets served at Bibiana Restaurant in downtown Washington, D.C. Joseph Silverman/The Washington Times /Landov hide caption

itoggle caption Joseph Silverman/The Washington Times /Landov

Dr. Alex Dromerick co-directs the Brain Research Center at the National Rehabilitation Hospital. Here he observes Stephen Jones, a policeman who was involved in a motorcycle accident. Becky Lettenberger/NPR hide caption

itoggle caption Becky Lettenberger/NPR

The Mall of America in Bloomington, Minn., has implemented a security program aimed at aiding the government identify suspected terrorists. Jim Mone/AP hide caption

itoggle caption Jim Mone/AP

The Mall of America, one of the nation's largest shopping and entertainment venues, is also home to its own counterterrorism unit. Dawn Villela/AP hide caption

itoggle caption Dawn Villela/AP