RETRO MOTION U.S. Marines motion to the operator of a multipurpose vehicle during a retrograde operation on Patrol Base Boldak in Afghanistan's Helmand province, Aug. 14, 2014. The operation was designed to retrograde the majority of excess gear and equipment, including air-conditioning units and containers for living quarters. SHARE: Download: Full Size (0.05 MB) Credit: VIRIN: 773762-V-ERY74-824.jpg Photo Gallery