SUMMER HEAT U.S. Marines participate in the annual Summer Heat training exercise on Marine Corps Air Ground Combat Center Twentynine Palms, Calif., June 28, 2009. During the exercise, the battalion conducted live-fire maneuvers and a massive force-on-force training evolution.The Marines are assigned to the 1st Marine Division's 1st Tank Battalion. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 645159-G-CLU31-042.jpg Photo Gallery