Airmen from the 28th Aircraft Maintenance Squadron stand at ease prior to a retreat ceremony at Ellsworth Air Force Base, S.D., April 18, 2014. Each month, a squadron on base performs a retreat ceremony at the base flagpole in front of the 28th Bomb Wing Headquarters building as a way of remembering and honoring the Air Force heritage. (U.S. Air Force photo by Airman 1st Class Rebecca Imwalle/released)