Detailed Explanation on Instagram: "Marco Siffredi was the first person ever to have successfully completed snowboarding down Mt. Everest on May 23, 2001. On September 8, 2002, the French daredevil reached the 29,000-foot summit of Earth’s highest point again, for a second descend on a more difficult route. Exhausted from the climb and the high altitude, Siffredi stood at the edge with his board, determined to proceed with his plan. After strapping on a fresh oxygen tank and bidding farewell to