The ridge topping the Hartmannswillerkopf mountains (Viel Armand in French) preserves a remarkable snapshot of World War I conflict. Their preservation is in part due to the fact that they are mostly rock cut plus the fact that their isolated position has not been developed for agriculture or construction.
Over 30,000 French and German troops diued during the conflict and the ridge changed hands many times. As well as miles of trenches, there are observation posts, underground personnel shelters,ammunition stores and mortar positions all preserveed in the rock.
A museum tells the story of the conflict and a large military cemetery gives some indication of the size of the death toll. The trench system itself can be freely explored.