Switzerland enjoys a 62,000-km network of well-maintained trails, of which 23,000 are located in mountainous areas. Many mountains attract a large number of alpinists from around the world, especially the 4000-meter summits and the great north faces (Eiger, Matterhorn and Piz Badile). The large winter resorts are also popular destinations in summer, as most of aerial tramways operate through the year, enabling hikers and mountaineers to reach high altitudes without much effort. The Klein Matterhorn is the highest summit of the European continent to be served by cable car.