In the far south lies the small town of Schopfheim next to the Black Forest, and the lake in the district of Eichen is a temperamental wonder of Mother Nature. For most of the time, it is a dry lake and only fills up occasionally in wet years. And this can happen overnight. This unusual body of water was first mentioned in 1772, when five young men drowned in it. Only a few days later, nothing would have happened to them. The water disappeared again and flowers began to bloom on the meadow. Scientists have never been able to fully explain how the lake appears and then quickly disappears again. However, they all agree that the Dinkelberg range of hills on which the Eichener Lake lies is largely made up of shell limestone. These are riddled with cracks and large cave systems in which the groundwater could accumulate. When there's sufficient water, it literally spurts out through the grass. The unpredictable lake grows to about 2.5 hectares in size.
This in itself is really quite mysterious, but it becomes even more curious when we consider the lake's famous inhabitants: ostracods, which have their gills on their legs and exist only here in the whole of Central Europe. As soon as the lake lives up to its name, these little creatures about two centimeters in length become active. Speed is of the essence: eat, grow, copulate. For the females, it also means quickly laying their eggs, which can wait for several years in dry conditions until the lake finally deigns to put in an appearance again. It's hardly surprising that the lake's mysterious appearance quickly becomes common knowledge by word of mouth. Within just a few days, newspapers begin to report on this natural wonder, by which time, countless walkers are out doing their rounds along the rare body of water. Sometimes, however, it disappears again, and all that remains is a pleasant walk along a path that appears to surround nothing more than a meadow.