Timber Treaders Marine Corps Capt. Cameron Heard, left, and Staff Sgt. Michael Birch walk on logs during the inaugural Challenge Reconnaissance at Camp Pendleton, Calif., April 27, 2017. The challenge comprises 24 miles of hiking, helocasting, scout swimming, a memory challenge, obstacle course, live-fire range, close-quarters tactics and two pool stations. Marine Corps photo by Cpl. Brandon Martinez SHARE: Download: Full Size (1.41 MB) Credit: Cpl. Brandon Martinez VIRIN: 170427-M-FK947-674C.JPG Photo Gallery