The Great Lakes (French: les Grands-Lacs), also called the Laurentian Great Lakes and the Great Lakes of North America, are a series of interconnected freshwater lakes located primarily in the upper mid-east region of North America, on the Canada–United States border, which connect to the Atlantic Ocean through the Saint Lawrence River. Consisting of Lakes Superior, Michigan, Huron (or Michigan–Huron), Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total area, and second largest by total volume containing 21% of the world's surface fresh water by volume. The total surface is 94,250 square miles (244,106 km2), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km3). Due to their sea-like characteristics (rolling waves, sustained winds, strong currents, great depths, and distant horizons) the five Great Lakes have also long been referred to as inland seas. Lake Superior is the second largest lake in the world by area, and Lake Michigan is the largest lake that is entirely within one country. The southern half of the Great Lakes is bordered by the Great Lakes Megalopolis.