Marines execute a “hell hole” rappel (left) and a skid rappel from the top of the rappel tower Feb. 11 on Camp Hansen, Okinawa, Japan during the beginning phase of helicopter rope suspension training. HRST is a course that trains Marines on the necessary skills required to perform a wide variety of rappelling techniques they may need to use in a combat operation. Throughout the course the Marines will learn how to tie specific knots used in creating a rappel harness with rope, rappelling techniques, and the basic rules one needs to follow when rappelling. (U.S Marine Corps photo by Cpl. Matt S. Myers/Released)