Iain Stewart journeys across the oceans to explore the most powerful giant waves in history, with ten remarkable stories about tsunamis.These massive waves can be taller than the biggest skyscraper, travel at the speed of a jet plane and when they reach land, rear up and turn into a terrifying wall of water that destroys everything in its path. These unstoppable, uncontrollable forces of nature caused the ruin of an entire ancient civilization, may have played a small part in the demise of the dinosaurs, and in World War II were used as a weapon. Yet astonishingly, two men who surfed the tallest wave in history - half a kilometre high - survived.