A U.S. Marine keeps a keen eye inside a building during a dismounted patrol training exercise at Saber Strike 2012. The Marines assigned to 3rd Battalion, 25th Marine Regiment were on a mission to investigate unfamiliar terrain. 3/25 is a Pennsylvania-based Reserve unit. Saber Strike 2012 is a multinational, tactical field training and command post exercise that involves more than 2,000 personnel from the U.S. Army's 2nd Cavalry Regiment, Pennsylvania National Guard, 21st Theater Sustainment Command, the 4th U.S. Marine Division, the 127th Wing of the Michigan Air National Guard, Estonian, Latvian, and Lithuanian armed forces, with contingents from Canada, Finland, France and the U.K. The exercise, led by U.S. Army Europe, is designed to enhance joint and combined interoperability between the U.S. Forces and partner nations, and will help prepare participants to operate successfully in a joint, multinational, interagency, integrated environment.