The Alps receives higher precipitation in the Northern part.
The water runoff feeds several large rivers like Rhine, Rhone, and Po River. Its elevation and exposure to maritime air masses and to the suns rays are the prime variables influencing its vegetation, creating a beech forest despite its cool temperature. Above the 1800 meter margin is the treeless zone; however, this area has other Alpine flora including rhododendron, edelweiss, among others.
Places around the Alps can be crossed through passes. Passes are depressions in the mountains to which the valley leads from the plains and hilly pre-mountain zones. Passes have been made for war, commerce and later by pilgrims, students and now popularly for tourists. Today, the Alps is famous as the center for transit trade as it connects the Central and Southern Europe.