The «Lai da Palpuogna» (Palpuogna Lake) (2622 Meters above Sea level) is a very beautiful and famous lake in the Albula Range of the swiss Alps (right underneath the albula pass).
The Lake is also very mysterious because there is an second, underground lake underneath the visible lake. That's the reason why you may not swim here - you would be pulled-down!
On some places, you can see the wholes to the underground lake.
The Palpuogna-Lake has been selected (by the swiss population) in a 2007 swiss television broadcast show to the most beautiful Place of Switzerland.