C'mon, Matt! Attention all stations. Stand by for an urgent tsunami warning for the Big Island and the islands of Maui, Lanai and Oahu. This warning is based on a 7.5 magnitude earthquake near Kailua-Kona. Could it really happen? Could a giant wave really menace the beaches of Hawaii? There is something out there and it threatens coastlines around the world. It's one of nature's least understood forces: Tsunami! We often see hurricanes and typhoons that churn up higher-than-normal tide. They can flood low-lying coastal communities. But as dangerous as these storm surges can be, they are not the worst of all possible waves. The real monsters are tsunamis, freak waves usually produced by undersea disturbances like earthquake. They can race across entire oceans and swallow cities whole. And they can leave tens of thousands dead. Throughout history, tsunamis have generated legendary disasters... Reversion the shores nearly every ocean and sea. Without warning and without mercy. killer waves have struck again and again. And tsunamis are as mysterious as they are deadly, because so few have ever been observed by scientists. This extraordinary footage was shot in 1952, in the Kuril Islands off Russia's northern Pacific Coast.