Spc. Bryan Clark, an infantryman from 1st Battalion, 187th Infantry Regiment, 3rd Brigade, 101st Airborne Division (Air Assault), checks identifications Dec. 12, at gate 4 on Fort Campbell. The gate guards help maintain security at the perimeter of the installation by diligently checking vehicles coming on post. (U.S. Army photo by Sgt. Leejay Lockhart, 101st Sustainment Brigade Public Affairs)