Enlarge / Extreme sportsman Ross Edgley comes face to face with a great hammerhead shark in the waters of Bimini in the Bahamas. (credit: National Geographic/Nathalie Miles) Ultra-athlete Ross Edgley is no stranger to pushing his body to extremes. He once ran a marathon while pulling a one-ton car; ran a triathlon while carrying a 100-pound tree; and climbed a 65-foot rope over and over again until he'd climbed the equivalent of Mt.