The largest lake globally, equivalent in size to Japan, is just one of over 304 million lakes worldwide containing either stagnant or slowly flowing water. Many of these colossal bodies of water could be classified as inland seas despite being landlocked and linked to the oceans through rivers or narrow passages.
Spanning 386,400 sq km (149,200 sq mi), the Caspian Sea holds the title of the world’s largest lake, straddling both Europe and Asia. Surrounded by Kazakhstan, Russia, Azerbaijan, Iran, and Turkmenistan, this immense lake sits approximately 27 meters below sea level.
In contrast, the Caspian Sea dwarfs Lake Superior, which spans 82,000 sq km (31,660 sq mi) and lies on the Canada-US border, nearly five times in size. Accounting for a significant 44% of the world’s lake waters, the Caspian Sea is estimated to be around 30 million years old, becoming landlocked approximately 5.5 million years ago.
Flowing into the Caspian Sea is Europe’s longest river, the Volga, acting as the primary source of freshwater for this colossal water body. The sea’s water is relatively fresh due to this inflow, with over 130 rivers, including the Ural River and the Kura River, feeding into it.
Hosting numerous small islands mainly in its northern region, the Caspian Sea lacks islands in its deeper sections, with Baku in Azerbaijan being the largest city along its shores. Known for its diverse species and famous for caviar and oil production, the sea’s ecosystem has suffered due to pollution from the oil industry and dams on its draining rivers.
With reports indicating a potential decrease in sea depth due to global warming, the Caspian Sea is home to over 850 animal and 500 plant species, some of which are unique to the region. Notably, six critically endangered sturgeon species, the Caspian seal, and beluga are among the iconic inhabitants of this vast lake.
