Lochmatter and Knubel were the first well-informed guides of the Matterhorn and were consequently pioneers in the development of modern tourism in the valley of St. Niklaus and particularly in Zermatt. They also had a monopoly on Matterhorn ascents. Moreover, as the first Swiss guide to do so, Knubel climbed a mountain outside the Alps in 1874, the highest European summit, Elbrus in the Caucasus. Pollinger invented the double-rope system of descent, which he used successfully at the Ridge of Ferpècle. Imboden was the first Swiss to ascend an (unnamed) 6,000 meter-high mountain in the Himalayas in 1883, where the highest mountains in the world are located.