Original: The boundary between Asia and Europe is conventionally considered to run through the Dardanelles , the Sea of Marmara , the Bosporus , the Black Sea , the Caucasus Mountains , the Caspian Sea , the Ural River to its source and the Ural Mountains to the Kara Sea near Kara , Russia .
Simplified: This boundary runs North-South down the Ural Mountains in Russia , along the Ural River to the Caspian Sea , and through the Caucuses Mountains to the Black Sea .