Wikipedia
Totensee
Totensee (or Totesee) is a small natural lake ( 0.18 km²) at the Grimsel Pass in the canton of Valais, Switzerland. It is used as a reservoir and drained into Grimselsee.
In November 2006, the lake's entire trout population died, possibly due to algae.
The name Totensee (also: Lake Toten, literally "Lake of the Dead") is said to be derived from soldiers of Duke Berchtold V of Zähringen driven into the lake by the people of Valais.