Lance Cpl. Sean Carolla, a rifleman with the 2nd Battalion, 5th Marine Regiment, 1st Marine Division, currently serving as the Battalion Landing Team for the 31st Marine Expeditionary Unit, trudges through stagnant water, narrow tunnels and barbed wire during endurance course training at the Jungle Warfare Training Center in Okinawa, Japan, on April 23.

From the new and improved Frontline Photos.

UPDATE: Story and more pics at