Guarda su Altadefinizione. See the world's first MRI scan of a great white shark as Ultimate Shark reveals the extreme engineering and predatory abilities of one of nature's most near perfect predators. Hear firsthand accounts of people who survived harrowing encounters, including a surfer who was bitten on the arm and leg, towed by the surfboard ankle strap and miraculously escaped only with minor injuries. National Geographic demystifies the true motives and power behind their behavior.