Schlachtensee

In the location's words:

The Schlachtensee lake in south-west Berlin is a great place for relaxation and leisure activities. Nestled in green surroundings, the lake offers clear water for swimming and rowing. For the more energetic, the surrounding paths are ideal for walking, jogging or cycling. Cozy shore areas also invite you to simply linger and picnic. The Schlachtensee is perfect for a short trip into nature, just a stone's throw from the city center. :)