But even Dolomites and Chamounix aiguilles are not inexhaustible, and the number of unconquered summits gradually diminished. The rapid opening up of the Alps has naturally turned the attention of men with the exploring instinct and ample means to the exploration of the great mountain ranges beyond Europe. This does not fall within the scope of the present volume, and we need only remark in passing that British climbers have played an important part in the campaigns against the fortresses of the Himalaya, Caucasus, Andes, and Rockies. Meanwhile the ambitious mountaineer was forced to look for new routes on old peaks. Now, a man in search of the easiest way up a difficult peak could usually discover a route which was climbable without severe technical difficulty. On a big mountain, it is often possible to evade any small and very difficult section. But most mountains, even our British hills, have at least one route which borders on the impossible, and a diligent search will soon reveal it. Consider the two extremes of rock-climbing. Let us take the Matterhorn as a good example of a big mountain which consists almost entirely of rock. It is impossible to find a route up the Matterhorn which one could climb with one’s hands in one’s pockets, but the ordinary Swiss route is an easy scramble as far as the shoulder, and, with the fixed ropes, a straightforward climb thence to the top. Its Furggen Ridge has been once climbed under fair conditions and then only with a partial deviation. It is extremely severe and dangerous. The task of the mountaineers who first assailed the Matterhorn was to pick out the easiest line of approach. The Zmutt, and in a greater degree the Furggen routes, were obviously ruled out of consideration. The Italian route was tried many times without success before the Swiss route was discovered. Of course, the Matterhorn, like all big mountains, varies in difficulty from day to day. It is a very long climb; and, if the conditions are unfavourable, it may prove a very difficult and a very dangerous peak.