The Caspian Sea is inside the European arid region (or desert). That is how the two are related to each other.
It runs through the lowlands [desert] to the Caspian Sea
The Caspian Sea is in Europe.
EuropeThe Caspian Sea is located in Europe
The Caspian sea is located where Asia meets South-East Europe.
Caspian Sea is in Asia; it is an error to consider this sea in Europe.
The Caspian Sea is located between Europe and Asia.
The Caspian Sea is located on the continental divide of Europe and Asia.
The Caspian Sea is partially in Europe, but mostly in Asia.
It runs through the lowlands [desert] to the Caspian Sea
Europe
The Caspian Sea is located on the continental divide of Europe and Asia.
The Caspian sea is located between southeast Europe and western Asia. So you could say Europe and Asia.