The Alpine Mountain System consists of chains of young fold mountains that lie south of the above mentioned plateaux, from the Atlantic Coast in the west to the Caspian Sea in the east. They have high peaks, deep valleys and rugged slopes. They are made up of several parallel ranges. Earthquakes and volcanic eruptions are common here. The Alps is the most important mountain system which extends like an arc separating Italy from France and Switzerland. Mont Blanc (4,807 m) is the highest peak in the Alps. In the west are the Sierra Nevada in southern Spain and the Pyrenees, which form a natural boundary between Spain and France.
