1.5 km south of Daun in the Eifel and in the German state of Rhineland-Palatinate.

Parts of the lake are used for bathing in summer, which has a marked effect on the surrounding nature reserve.

All that remains, however, is a narrow ridge of slate, grauwacke and sandstone between the maar and the neighbouring Lieser valley.

There is a footpath around the maar on which one can view the Devonian rocks around the lake.

Numerous volcanic bombs may be found, especially in the western area of the maar.