Kuma–Manych Depression
The Kuma–Manych depression (Russian: Кумо–Манычская впадина, romanized: Kumo–Manychskaya vpadina) is a geological depression in southwestern Russia that separates the Russian Plain to the north from Ciscaucasia to the south. It is named after the Kuma and Manych rivers.
Geography

Kuma–Manych depression is sometimes regarded as a definition for the natural boundary between Asia and Europe.
The Rostov Nature Reserve is located within the depression.