Ninetieth Logistics Readiness Squadron Airmen conduct a ruck march along the streets of F.E. Warren Air Force Base, Wyo., Sept. 11, 2014. The Airmen marched in remembrance of the Sept. 11 attacks against the U.S. and to honor F.E. Warren's first responders on the 13th anniversary of the attacks. (U.S. Air Force photo by Lan Kim)