The salty Caspian Sea (north of Iran) is the world's largest land-locked body of water. It contains approximately 18,900 cubic miles of water (78,700 cubic kilometers).
Lake Baikal (in Russia, just north of Mongolia) is the world's largest freshwater lake in terms of volume. It contains about 5521 cubic miles of water (23,000 cubic kilometers), or approximately 20% of Earth's fresh surface water. This is a volume of water approximately equivalent to all five of the North American Great Lakes combined.
The salty Caspian Sea has the greatest surface area of any lake at 143,200 square miles (370,886 square kilometers). Lake Superior, on the United States/Canada border is the freshwater lake with the greatest surface area at 31,700 square miles (82,103 square kilometers).