Černé jezero

Černé jezero in the Bohemian Forest is the largest and deepest natural lake in the Czech Republic.This triangular lake surrounded with spruce forest is located about 6 km northwest of Železná Ruda under a 300-metre-high cliff on Jezerní hora. It is of glacial origin, a product of the Würm glaciation. The water in the lake is oligotrophic. There is a natural outflow through Černý potok, a short stream which is a tributary of the Úhlava River. The main European water divide runs across the mountain just above the lake. As a consequence, Černé jezero belongs to the water basin of the Elbe, which finds the North Sea, while Čertovo jezero just 2 km away drains into the Danube and thence the Black Sea.

The oldest pumped-storage hydroelectric plant in the Czech Republic is located here; the lake serves as its upper reservoir.

Source: Wikipedia