Add Yahoo as a preferred source to see more of our stories on Google. When you buy through links on our articles, Future and its syndication partners may earn a commission. Hells Canyon, America's ...

For millennia, water has carved its way down mountains, creating gorges with rushing streams and peculiar rock formations ...

The origin story of Hells Canyon, North America's deepest river gorge, has long been unclear to scientists. But new research estimates it formed about 2.1 million years ago when a dramatic flood event ...