Europe has a well developed network of rivers. The largest rivers on the continent are situated in the Russian planes. The largest river in Europe is Volga Kama and its tributaries Oka. Other major rivers are the Don, Dnieper, Dniester. The rivers Pechora and Northern Dvina flow into the Arctic Ocean and the rivers Neman, Neva, Vistula, Odra (Oder), Elba (Laban) and others flow into the Atlantic Ocean. The rivers in Fennoscandia and on the Kola Peninsula are short, torrential with many rapids and waterfalls (Glomma, Tura, etc.). The largest rivers in Western Europe are the Danube, Rhine, Seine, Thames, Loire, Garonne, Rhone and others. All these rivers are deep and with high waters almost all year round. Rivers in Southern Europe are more shallow and in the summer the water levels go down. Some of these are the rivers Duero, Tagus, Gvadiana, Tiber, Arno, Vardar, Struma, Mesta, Maritsa, Iskar. Lakes are unevenly distributed in Europe and are very different in origin and water regime. The largest number of lakes are of glacial-tectonic origin: Ladoga, Onega, Vänern, Vättern, Mälaren, Imandra, Geneva, Vierwaldstättersee, Como, etc. In Europe there are also many alpine lakes. In the tectonic valleys of the Balkan Peninsula are situated Lake Prespa, Ohrid and others. The largest lake in Europe is the Caspian Sea. The total area of glaciers on the continent today is about 120 000 km2. Most of them (about 100,000 km2 are on the Arctic Islands, 785 km2 are in Iceland, about 5000 km2 – in Scandinavia and around 4140 km2 – in the Alps).