The St-Léonard underground lake
The mysterious cavern was discovered in 1943 by Jean-Jacques Pittard, but the lake was not open to the public until 1949. The St. Leonard underground lake is the largest of its kind in Europe: it is 300m long and 20m wide. The boat trip to the lake lasts over half an hour and can accommodate up to 40 people (commentary is available in several languages). A delightful planted terrace with a small children’s playground plus a brand-new educational area, with info on how the cavern and the Alps were formed, invite you to linger.