From the Ballon d'Alsace, the descent to Lac d'Alfeld via the D 465 is stunning. As you emerge from the forest, the water appears at the bottom of a cirque of glacial origin, surrounded by wooded hills where the rock shows through in places. With a surface area of 10ha and a depth of 22m, it is reserved for fishing. The dam, a 337m structure that retains the lake's water, is built on a moraine left by the glaciers.