Staff Sgt. Kory Peterson, 28th Civil Engineer Squadron pavement and construction equipment technician, sprays down gravel with water during a sidewalk construction project at Ellsworth Air Force Base, S.D., April 4, 2012. Wetting the gravel makes it easier to compact and reduces the chances of cracking in the future. (U.S. Air Force photo by Airman 1st Class Alystria Maurer/Released)