Mysteries of the Great Lakes

Dubbed 'inland seas' by early European explorers, the Great Lakes have some of the most spectacular wilderness scenery on earth, and a fifth of all the planet's fresh water. The waters pass by towering cliffs dotted with early Native American pictographs, caribou and moose grazing on the shores, over giant prehistoric sturgeon lurking among thousands of shipwrecks and past nearly 40 million people who live along the more than 10,000 miles of coastline.