The Casinoweiher, which was dammed up in 1861 by the construction of a 300 m long earth wall, is probably the most beautiful remaining relic of the lively mining activity in the former Altenberg and the surrounding area in the 19th century.
This almost 5 hectare reservoir was created by the mining company "Vieille Montagne" as a water reservoir for washing the Galmeierze and the resulting deposits can still be seen in the form of heaps of heaps that protrude laterally over the dam.