Saint-Léonard underground lake
Saint-Léonard underground lake (French Lac souterrain de Saint-Léonard) is located at Saint Léonard in the canton of Valais, Switzerland. With a length of 300 and a width of 20 m it is the largest underground lake in Europe. It was discovered in 1943 by Jean-Jacques Pittard. Prior to 1946 the water-level was much higher, but an earthquake with a force of 5.6 on the Richter-scale opened additional fissures in the cave on January 25, 946. Its water is constantly at 11 °C (52 °F).
Access to the lake was closed from 2000 to June 2003, after the stability of the site was improved by the addition of more than 5000 bolts driven into the ceiling.
Source: en.wikipedia.org/wiki/Saint-Leonard_underground_lake – 29.09.2011
Saint-Léonard Underground Lake
He who views the Saint-Léonard Underground Lake does it in connection with artifical light, technical equipment and together with other persons.
In natural darkness and unaffected by humans, such an underground lake would have still a much more impressive character.