Discover how colossal floods transformed the ancient landscape. All over the world, scientists are discovering traces of ancient floods on a scale that dwarfs even the most severe flood disasters of recent times. What triggered these cataclysmic floods, and could they strike again?

In the Channeled Scablands of Washington State, the level prairie gives way to bizarre, gargantuan rock formations: house-sized boulders seemingly dropped from the sky, a cliff carved by a waterfall twice the height of Niagara, and potholes large enough to swallow cars.

Like forensic detectives at a crime scene, geologists study these strange features and reconstruct catastrophic Ice Age floods more powerful than all the world’s top ten rivers combined.