The Voie Sacrée — the Sacred Way — was the single road on which the entire French defence of Verdun depended. The Germans had cut every railway line into the city; for ten months the road from Bar-le-Duc was the lifeline, with thousands of trucks moving men and shells around the clock.
The road itself can still be driven. Concrete milestones every kilometre are each topped with a stylised infantry helmet (the Adrian helmet, introduced in 1915). The route starts in Bar-le-Duc and joins the D1916 just south of Verdun; an hour's drive end to end.