Unterstand-Stollen + Kiesling Tunnel

The Kiesling Tunnel is a tunnel approximately 650 meters long, designed to move German troops unseen to the Maasbogen Stellung. The largest section, including the main entrance, is located on private property and is not freely accessible. It is sealed off there with a steel gate and serves as a winter hibernation site for bats and as a habitat for foraging bats during the summer. The section of the Kiesling Tunnel that opens into both the frontline (the Hauptwiderstandslinie, or HWL) and the second line, the Schloß-Graben, is also located in a private forest, but without any closure.

During the war, these connecting tunnels (there are three in total along the entire Maasbogen line) were sealed with a masonry wall made of rock blocks. This was done by the Germans themselves once troops were already stationed in the trenches, to prevent the enemy from using these tunnels against them if the frontline were to be overrun. A second reason for sealing these tunnels was a common practice that is often left unspoken but was widely used on both sides of the front. This was to prevent German soldiers from fleeing when the violence of war became too overwhelming. If you look at the topography of the Maasbogen Stellung, any soldiers attempting to flee would have had to run across a 600-meter-long ridge in full view, completely exposed to enemy fire, and also within range of their own rear troops, who would undoubtedly have been ordered to open fire on deserters as a deterrent to others who might witness such attempts.

In the second line, the Schloß-Graben, we discovered an Unterstand-Stollen. This is a standard dugout with two entrances connected by a passage that functioned as a Bereitschaftsraum, the living space where the soldiers stayed.

Notably, the left-hand entrance at the rear has a breach in the rock wall. Anyone looking through this opening can see a wide and high tunnel, which is in fact the Kiesling Tunnel. It is likely that the pioneers who excavated these tunnels accidentally broke into the Kiesling Tunnel, unintentionally creating a connection with the second line. Originally, the Kiesling Tunnel would probably have connected only the frontline with the rear areas.

We are now standing in front of the sealed section of the Kiesling Tunnel. Behind this wall lies the 600-meter-long passage that opens into a valley along the northern flank of the Meuse.

In September 1918, an entire battalion of 800 men strong from the 18. Königliche Sächsische Infanterie-Regiment Nr. 192 marched through here, after which the tunnel was sealed by the pioneers to prevent these men from being able to flee. The fate of these 800 German soldiers remains unknown.

We are now behind the sealed wall of the Kiesling Tunnel, beyond the frontline, the Hauptwiderstandslinie. We have just documented a section of the Kiesling Tunnel hidden between the frontline and the second line, which is closed off by two masonry walls to the east and west of the tunnel.

The section beyond this wall has also been visited and will be documented in a separate post dedicated specifically to that part of the Kiesling Tunnel.

We discovered this wall painting, left behind by the pioneers who dug this tunnel as early as 1916: 3. Bayerische Feldpionier-Kompanie. The 3. Bayerisches Pionier-Bataillon was a pioneer unit of the Bavarian Army within the Imperial German Army. The battalion was established in 1900, played a major role during the First World War, and was among others attached to the 9. Bayerische Ersatz-Brigade. The battalion was mobilised in 1914 and split into two field battalions.

On the way back to our exit in the Schloßgraben, we briefly pass by the dugout that was the original focus of this post, before we were drawn away by a fracture in the rock face that led us into the Kiesling Tunnel. In these final photos, you can see the condition of the soldiers’ living quarters as observed in 2025, more than one hundred years after the First World War.

Please note that this applies to all tunnels we explored here: there is always a risk of collapse, a danger of oxygen deficiency, and the possible presence of unexploded ordnance still hidden among the rock debris. The site also appears to be privately owned and is not actually freely accessible (at the time of our investigation, we were not aware of this).