The underground lake of St. Leonard

There are some interesting things in Switzerland that I had no idea existed -- such as the underground lake of St. Leonard.

The lake is located between Sion and Sierre in the heart of the Swiss Alps.  It's about 300 meters long -- which doesn't sound very big, but it is the largest natural underground lake in Europe so I guess it's big enough.

If you visit it, you can take a little boat ride across the lake and back.  It's surprisingly clean smelling. Considering you are underground and surrounded by water, it doesn't smell like a musty cave. The air actually smells fresh.

There is also trout in the lake.  My French is not excellent (it sucks), so I'm not sure if they put the trout in there to monitor the acid in the water to make sure it's still healthy or if the trout are naturally there. Whatever the case, they are there and they look happy swimming around -- so the water must be clean.

And to make this cave even more interesting, there is this -- because the acoustics are so fantastic in the cave, they sometimes have concerts in there.

The entire boat ride only takes about 30 minutes, but if you are already in Sion for other reasons, it's worth dropping in to check it out.