Iain Stewart journeys across the oceans to explore the most powerful giant waves in history, with ten remarkable stories about tsunamis. They can be taller than skyscrapers, travel at the speed of a jet plane and when they reach land, rear up and turn into a wall of water that destroys everything in its path. They 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 of war.