The Elbsandsteingebirge are a low mountain range built mainly of sandstone on the upper reaches of the Elbe river in Saxony and northern Bohemia. The characteristic feature of this highly rugged rocky mountain range is its extraordinary wealth of forms in a very small area. A special feature is the constant alternation of plains, gorges, table mountains and rocky areas with preserved closed forest areas. The diversity of the different sites has produced an enormous variety of species, e.g. ferns and mosses. The national park is an Eldorado for hikers and mountaineers.