View of the Carspach tunnels (Haut-Rhin) during the excavation process. The Kilianstollen was located on the German front line‚ which remained stable to the west of Altkirch between 1914 and 1918. This large underground shelter was constructed in early 1916 using mine engineering techniques. The shelter ran parallel to the trenches‚ at a depth of between 3.5 and 6 metres