The state of Thuringia is also known as the "green lung of Germany". Thuringia has both flat, fertile regions and extensive forests and low mountain ranges. In the far north, Thuringia borders on the Harz Mountains. The best-known region in the state, besides the cities of Erfurt, Weimar and Jena, is the Thuringian Forest, which stretches from the northwest along the river Saale for about 100 kilometers to the Werra near Eisenach. The Beerberg with 983 meters and the Schneekopf with 978 meters are the highest mountains of the Thuringian Forest.