Caspian Sea
The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, although it is not a freshwater lake. It contains about 3.5 times more water, by volume, than all five of North America's Great Lakes combined. The Caspian was once part of the Tethys Ocean, but became landlocked about 5.5 million years ago due to plate tectonics. The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it has no natural outflow other than by evaporation. Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans.
List of lakes
There are around hundreds of lakes, deep below the ice of Antarctica.
The Caspian Sea, located in western Asia on the eastern edges of Europe, is the largest lake on the planet. History records that it is called a sea because the Romans found it salty, especially in the southern reaches, and the name stuck. Oil and natural gas production platforms are replete along the edges of the sea. In addition, large quantities of sturgeon live in its waters, and the caviar produced from their eggs is a valuable commodity. Fresh water flows into the sea via the Volga River and Ural River in the north; however, the sea remains somewhat salty, central and south. The measured surface area is 371,000 sq km (143,244 sq mi), and he maximum depth is at 1025 m (3,363 ft). Additional details and map.