What is the border between Asia and Europe?

The border between Asia and Europe are Aegean Sea, the Dardanelles Sea of Marmora-Bosporous, the Black Sea, along the watershed of the Greater Caucasus, the northwestern portion of the Caspian Sea, and along the Ural River and Ural Mountains.

The boundary between Asia and Europe exists mostly for cultural and historial constructs. It is physically defined by the Ural Mountain as it creates a natural separation. The border is also followed by the Ural Sea and the Ural River. The countries that are considered transcontinental are Russia, Turkey, Kazakhstan, Azerbaijan and Georgia.