Explored for the first time in 1943, the subterranean lake of St-Leonard is located between Sion and Sierre in the heart of the Swiss Alps along the Rhone valley. With a length of around 300 meters this is the largest natural underground lake in Europe which can be explored by boat (swimming is forbidden).
You can take a 30 minute guided boat trip on the crystal clear water and comfortable 15 degree temperature. The acoustic is fantastic so unusual concerts can take place here.
In my opinion, as this is a rather short visit, it’s much recommended to couple it with another activity such as the fabulous hike of the bisse de Savièse (see dedicated post) not far from the subterranean lake.
The lake opens every day from April 24th until November 1st.
https://goo.gl/maps/dKd7mjW4y1LbZqKa9
https://www.sierretourisme.ch/en/st-leonard-underground-lake-429.html
#lacsouterrainstleonard #stleonardlake