Grüner See is a lake in the Wiehen Hills of the Osnabrück Landkreis in Lower Saxony, Germany. At an elevation of ca. 145 metres, its surface area is ca. 0.1 hectares. It is around 25km north of Bielefeld.
Wikipedia https://en.wikipedia.org/wiki/Grüner_See_(Lower_Saxony)
Address 38 Kellenbergstraße, 49328, Germany
Coordinates 52°15'48.532" N 8°27'15.883" E