Spc. Riley Krebsbach, Tomb Sentinel, Tomb of the Unknown Soldier, 3d U.S. Infantry Regiment (The Old Guard), places a rose at each of the four crypts of the Unknowns during his last walk ceremony, Oct. 8, in Arlington National Cemetery, Va. Krebsback served at the Tomb for 20 months from Feb. 2012 to Oct. 2014. (U.S. Army photo by Spc. Cody W. Torkelson)