Located on the slopes of the ‘Lerchenberg’ hill at Carspach (Haut-Rhin), the ‘Kilianstollen’ is set on the German front line, which remained stable to the west of Altkirch between 1914 and 1918. This structure is a large underground shelter (with the potential capacity to hold 500 soldiers), built between 1915 and 1916, where the soldiers from the trenches could seek shelter during enemy bombardments.

The German archives provide ample information on the construction of this subterranean shelter and the tragic events of 18th March 1918 which led to its partial destruction. That morning the German artillery spent the morning pounding the French lines with gas shells, while in the afternoon the French artillery responded by concentrating its fire on the section of the line near the Kilianstollen. A company from the 94th German reserve infantry regiment took refuge in this supposed stronghold. After several direct hits in rapid succession, the shelter collapsed and around thirty soldiers were buried in the rubble. A rescue operation was launched to free those who remained trapped underground, but the search was soon called off as technical constraints made it impossible to proceed. Twenty-one soldiers remained unaccounted for.

A preventive archaeological dig conducted in 2011 by the Interdepartmental Archaeological Service for the Rhine succeeded in locating these missing soldiers. Their remains were not moved after their deaths, meaning that they remained exactly as they were immediately after the collapse. These excavations provided new insight into the construction, design and use of this subterranean shelter, and much new information was also gleaned from examining the bodies and objects uncovered.