What is the world's largest saltwater lake?

The world's largest saltwater lake is the Caspian Sea. Despite its name, the Caspian is a landlocked body of water with no natural outlet to the ocean, so it is usually classified geographically as the world's largest lake.

The Caspian covers about 371,000 square kilometres—nearly five times the area of Lake Superior—and contains roughly 40–44% of the world's lake water. Its water is brackish, with salinity around 1.2%, far below average ocean salinity. The Volga River supplies about 80% of its inflow, while evaporation removes most of its water.

The Caspian formed as a remnant of the ancient Paratethys Sea and became isolated millions of years ago. Its coastline is shared by Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan. The name comes from the ancient Caspi people.

A common mix-up is the Dead Sea, which is much saltier but vastly smaller. The Caspian is also famous for sturgeon and caviar, oil production, and large changes in water level.