The surface of Lake Superior, one of the five Great Lakes on the North American continent, measures 31,820 square miles (82,435 square kilometers).
Its length alone is 383 miles (613 kilometers). Lake Superior has the largest surface of any lake on Earth, but it does not hold the most water.
Lake Baikal, which sits on a major fault in southeastern Siberia, contains one fifth of the total amount of freshwater on Earth, about 5,500 cubic miles (1,375 cubic kilometers) of water. Its surface area is easily one fourth or less than that of Lake Superior, but Lake Baikal is 5,712 feet (1,741 meters)—more than a mile (1.7 kilometers)—deep.
Lake Baikal claims to be the oldest lake in the world, too. Some 80 million years ago, the fault shifted, creating a depression, or graben. Then, 25 million years ago, it began to fill with water.