Photo - Northern Lake Michigan in winter.

Photo - Lake Superior ice formations.

The Great Lakes have not always looked the way they do today. In fact if you were to go back in time and visit Michigan 14,000 years ago, you would have found the Great Lakes area covered in a sheet of ice, called a glacier, that averaged over one kilometer thick. At rates of only a few centimeters per day, the glacier slowly made its way across the Great Lakes basin. It carved out deep valleys and moved large amounts of soil. As the glacier melted and moved towards Canada, it left behind a series of large holes that filled with meltwater from the glacier. These formed the basic shape of the Great Lakes. It wasn't until 6,000 years ago that the lakes took their final shape we see today.

Photo - Lake Fannie Hooe, Keweenaw County

The State of Michigan has over 6,360 lakes. This large number is due to the action of the glaciers across the land thousands of years ago and also resulted in the formation of the Great Lakes.

EXPLORE: Watch a Flash animation showing the formation of the Great Lakes.