one third of the land area of Switzerland, and about two thirds of the population live in this area. The population density on the plateau averages about 450 people per km2 (1,166 per square mile). In the regions around Lake Geneva, Lake Zurich and other cities, the population density exceeds 1000 people per km2. As well as the majority of the population, the Swiss Plateau is also home to the majority of industry, manufacturing and farming in Switzerland. The farms are generally small and very organized. Most farms include small meadows alternating with fields with a variety of crops and small wooded areas. Alps The Swiss Alps form part of a chain of mountains that stretch across southern Europe and isolate Northern Europe from the Mediterranean Sea. Several important passes through the Alps are located in Switzerland, and control of the passes has been important throughout Switzerland's history. The Alps have an average altitude of and cover nearly two thirds of the total surface area. Within the Alps there are 48 mountains that are or higher. The Alps are the watershed of Western Europe. The Rhine, together with its tributaries the Aare and the Thur drain about two thirds of the water into the North Sea. The Rhône and the Ticino drain about 18% of the water into the Mediterranean Sea. The Inn which flows into the Danube outside of Switzerland drains about 4.4% of the water into the Black Sea. The Swiss Alps also contain many of Central Europe's glaciers. There are about 1,800 glaciers which cover of the total glaciated area of the Alps. The Alps are a popular tourist destination and are one of the most recognizable symbols of Switzerland. The tallest point in Switzerland, Monte Rosa () in Canton Valais, is located in the Alps as is tallest mountain wholly in Switzerland, the Dom (). One of the most recognizable symbols of Switzerland, the Matterhorn, is also located in the Alps. The Matterhorn () is the seventh highest peak in the Swiss Alps and is the most photographed mountain in Switzerland. The tallest mountain in the northern outlier or Bernese Alps is the Finsteraarhorn (). Switzerland encompasses a significant portion of the south side of the Alps. Most of it is constituted by the canton of Ticino, almost reaching the plains of the Po and including Switzerland's lowest point on Lake Maggiore (). The canton of