The Great Lakes

The Great Lakes — Superior, Michigan, Huron, Erie, and Ontario — form the largest group of freshwater lakes on Earth by total area, holding about a fifth of all the liquid fresh surface water on the planet. Strung across the U.S.–Canada border in the heart of North America, they cover some 94,000 square miles of water, an inland sea so vast that storms raise ocean-sized waves and the far shores vanish below the horizon.

The lakes were carved by the great ice sheets of the last ice age, which gouged out their basins and left them brimming with meltwater. They drain east through the chain — Superior to Huron and Michigan, down to Erie over Niagara Falls, into Ontario, and out the St. Lawrence River to the Atlantic. Together they have shaped the cities, industry, and shipping of the whole region, a freshwater coastline thousands of miles long in the middle of the continent.