Underwater. Hidden. A volatile mix of a flash flood, an avalanche, and a volcanic pyroclastic flow causes massive sediment transport along the continental shelf.
An excerpt from the BBC: The river cascades through steep-sided gorges and churns around isolated towers of rock, before winding across a vast plain beyond. It is a torrent to rival the mighty Colorado River that carved out the Grand Canyon.
Yet this dramatic natural wonder has never appeared in any tourist photographs, nor does it feature on any maps. The reason? It lies two miles (3.2km) beneath the surface of the Pacific Ocean.