House Built Inside A Mountain, Alps, Switzerland

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.
Four-thousanders
The Union Internationale des Associations d'Alpinisme (UIAA) has defined a list of 82 "official" Alpine 4,000-metre (13,123 ft) summits. The list contains many subpeaks with little prominence, but important for mountaineering. There are the twelve four-thousanders with at least 1 km prominence.