The Ural Mountains form the traditional boundary between Europe and Asia, East and West. They extend 2500 km from the Kazakh steppes along the northern border of Kazakhstan to the frozen coast of the Arctic Ocean. The Urals are among the world´s oldest extant mountain ranges. They were formed in the late Carboniferous period, when a continent consisting largely of Siberia collided with the supercontinent that contained much of the world´s land at the time. Europe and Siberia have remained joined together ever since.