Last summer a giant wave swept through a remote fjord in southeast Alaska leaving destruction in its wake.
The event went largely unreported at the time, but a new scientific analysis shows it was caused by a massive landslide.
An incredible 64 million cubic metres of rock the equivalent of 24 Great Pyramids splashed into the water below. The sheer power of that amount of rock plunging into the fjord in under a minute created a gigantic wave almost 500 metres tall.
Only the time it happened in the early hours of the morning prevented tourist cruise ships being caught up in the devastation, say the researchers.
Dr Bretwood Higman, an Alaskan geologist, who saw for himself the damage at Tracy Arm Fjord, said it was "a close call".
