What large sea that is actually a lake located at 40 degrees north and 50 degrees east?

The large sea that is actually a lake located at those coordinates is the Caspian Sea. Despite its name, the Caspian Sea is the world's largest enclosed inland body of water, classified as a lake. It is bordered by several countries, including Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan. The lake is known for its unique ecosystem and significant oil and gas reserves.