A Marine with Battalion Landing Team 2nd Battalion, 7th Marines (BLT 2/7), 31st Marine Expeditionary Unit (MEU), uses a hasty sling to rappel down a 40 foot cliff during independent training at the Camp Gonsalves Jungle Warfare Training Center, April 27. The independent training was a rehearsal for the Endurance Course, a more than three mile hike through thick jungle terrain, where Marines must negotiate 32 obstacles designed to challenge them physically and mentally. (Official Marine Corps photo by Cpl. Michael A. Bianco) - A Marine with Battalion Landing Team 2nd Battalion, 7th Marines (BLT 2/7), 31st Marine Expeditionary Unit (MEU), uses a hasty sling to rappel down a 40 foot cliff during independent training at the Camp Gonsalves Jungle Warfare Training Center, April 27. The independent training was a rehearsal for the Endurance Course, a more than three mile hike through thick jungle terrain, where Marines must negotiate 32 obstacles designed to challenge them physically and mentally. (Official Marine Corps photo by Cpl. Michael A. Bianco)