All the eight Šumava lakes are situated in rock depression, so-called cirques deepened in ice ages by small glaciers. Five of them are on the Czech side, three others on the Bavarian side, at altitudes of 1000 to 1100 m. These cirque glaciers returned several times to their rock cradles and they always damaged the surrounding rock, so that it was gradually disintegrating and crashing down and progressively changing in a nearly perpendicular several hundreds meter high wall…