House Built Inside A Mountain, Alps, Switzerland

The secondary chain of the Alps follows the watershed from the Mediterranean Sea to the Wienerwald, passing over many of the highest and most famous peaks in the Alps. From the Colle di Cadibona to Col de Tende it runs westwards, before turning to the northwest and then, near the Colle della Maddalena, to the north. Upon reaching the Swiss border, the line of the main chain heads approximately east-northeast, a heading it follows until its end near Vienna.
Principal passes
The Alps does not form an impassable barrier; It has been traversed for war and commerce, and later by pilgrims, students and tourists. Crossing places by road, train or foot are called passes. These are depressions in the mountains into which a valley leads from the plains and hilly pre-mountainous zones.