Which inland body of water is the world's largest lake by surface area?

The world’s largest lake by surface area is the Caspian Sea.

Despite its name, the Caspian Sea is conventionally classified as a lake because it is an enclosed inland body of water with no natural outlet to the world’s oceans. Its surface area is roughly 371,000 square kilometres, vastly exceeding that of Lake Superior or Lake Victoria.

The Caspian is saline rather than freshwater and is bordered by five countries: Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. Water levels and reported area vary, partly because of evaporation, river inflow and long-term climate fluctuations.

The name creates the most common quiz trap. Geologically, the Caspian occupies a remnant of the ancient Tethys Ocean, so some classifications describe it as a small ocean. Under the standard geographic convention used in trivia, it is the largest lake.