What is "griebnitzsee"

Griebnitzsee is a lake in the western outskirts of Berlin, the capital city of Germany. At an elevation of 29.4 m, its surface area is ca. 0.592 km². The lake forms the border between the German states of Berlin and Brandenburg. It is bordered in the north by the Wannsee district of Berlin, and in the south and west by the Babelsberg district of Potsdam in Brandenburg.