The main chain of the Alps follows the watershed from the Mediterranean Sea to the Wienerwald, defining the northern border of Italy. It then passes over many of the highest and most famous peaks in the Alps. From the Colle di Cadibona to Col de Tende it runs to the west before turning to the northwest and then, to the north, near the Colle della Maddalena. Upon reaching the Swiss border, the line of the main chain goes about northeast, a heading it follows until its end near Vienna.