The first site to be designated a nature reserve in Alsace. 150 species of birds, 40 species of dragonflies, as well as tree frogs and wild boar all coexist here among the reed beds, ponds, marshes and moorland. Six marked paths, including the observatory path, allow you to get a good look at them. The imperial fish farm, built in 1852 in order to restock the rivers, was the first industrial fish farm in Europe. Today the buildings house an Introduction to Nature Centre, a research centre, a salmon farm and two lovely exhibitions.