Volunteers pass out water to runners during the Marine Corps Marathon's (MCM) annual Run Amuck event at Marine Corps Base Quantico, Va., June 13, 2015. The Run Amuck is the MCM's messiest mud and obstacle course consisting of a four-mile trail with 21 challenges to include a mud trench, low crawl and a mud pit. The event also included a scaled down two-mile version of the course, the Mini Run Amuck. (U.S. Marine Corps photo by Lance Cpl. Timothy A. Turner/Released)