U.S. Airmen form a line to pass sandbags down in order to build a defensive fighting position during a bivouac exercise at Joint Base Langley-Eustis, Virginia, Oct. 15, 2024. The bivouac simulated the setup of a base in contested territory from the ground up, training Airmen in multiple skills to ensure mission success. (U.S. Air Force photo by Senior Airman Ian Sullens)