Two participants reach the top of the hill after conquering a water obstacle during the annual Marine Corps Marathon's Run Amuck. Run Amuck, the Marine Corps Marathon's messiest mud and obstacle event, hosts 4,000 runners who face arduous obstacles and plenty of mud along a 4 mile course on June 14, 2014 throughout Marine Corps Base Quantico Va. (U.S. Marine Corps photo by James H. Frank/Released)