https://www.jungfrau.ch/de-ch/grindelwaldfirst/bachalpsee/

Bachalpsee in Switzerland is a gem in the Jungfrau region, offering stunning views of the Eiger, Mönch, and Jungfrau mountain peaks. When it's not windy you're able to see the reflection of the mountains in the lake!

The Bachalpsee is accessible via a scenic cable car ride from Grindelwald and a short hike (see seperate pinpoint). The hike from First to the lake is an easy, broad path. It takes around 50 minutes to get there. Whether you're chilling by the water or continue hiking to Faulhorn summit, you will love it.

Note: There is going to be lots of people there, especially because it is easy to reach. I recommend getting there early or even consider sleeping in the First Mountain Hotel or the Faulhorn Berghotel to be able to catch the sunrise at the lake or just be there before the cable car starts operating.