Established in 1953, the largest reserve in the Central Balkan National Park, of total area 4,220.2 ha. In 1997 was declared a biospheric reserve. Forest ecosystems cover over 71 % of its territory. Of the 9 reserves in the National Park this the richest place in endemic plant species -16 Bulgarian and 13 found also in other areas of the Balkans. It is the typical dwelling-place of very rare animals like the wild goat, brown bear, golden eagle and others. Here is the highest waterfall in Bulgaria - Raiskoto Praskalo (124 m). The reserve is poorly unexplored because of its extremely difficult terrain.