Lake Baikal is the largest freshwater lake by volume in the world, containing 22 to 23% of the world's fresh surface water. With 23,615.39 km3 (5,670 cu mi) of fresh water, it contains more water than all of the North American Great Lakes combined. With a maximum depth of 1,642 m (5,387 ft), Baikal is the world's deepest lake. It is among the world's clearest lakes and is the world's oldest lake, at 25–30 million years. It is the seventh-largest lake in the world by surface area.