Question

What is considered as Earth's largest inland lake?

Answer 1

Usually the Caspian Sea, but some classify this as a sea instead of a lake because it was formerly attached to the oceans. Lake Superior would be next.

Explanation:

See the following for more on the Caspian Sea: https://en.wikipedia.org/wiki/Caspian_Sea

https://en.wikipedia.org/wiki/List_of_lakes_by_area contains a ranking of lakes by area, including the remark anout the Caspian Sea noted above.