From Durrenbach, the cycle route goes along the former railway line parallel to the D27 and runs past the attraction park at the spa town of Morsbronn-les-Bains. After Woerth, with its museum retracing the history of the Battle of 6th August 1870, the cycle route take us to the pretty village of Lembach where Four à Chaux fort stands guard and is open to visitors. A stone's throw from Lembach, 12th-century Fleckenstein castle stands proud on a sandstone ridge looking out over the landscape. Built in the late 1880s and brought into service in 1899, this unique railway line was used to transport goods, travellers, local inhabitants from the upper Sauer valley and visitors going to take the waters at Morsbronn-les-Bains. Later, in 1930, it was also used to service Four à Chaux and Hochwald, which were major bastions of the Maginot Line then under construction. In service until 1975, it was converted into a green cycle route in 1990 and provides a dedicated cycle trail running along the river Sauer for 13km.