Air Force Office of Special Investigations Expeditionary Detachment 2405 and 455th Expeditionary Security Forces Squadron members ruck march Dec. 21, 2016 at Bagram Airfield, Afghanistan. The two units held a “Ruck March to Remember” six fallen comrades who lost their lives during an improvised explosive device attack one year earlier. (U.S. Air Force photo by Staff Sgt. Katherine Spessa)