The Caterpillar was part of the Hill 60 battlefield, and was an area of spoil created when the nearby Ypres railway put a cutting through this area in the nineteenth century. The front line here was established after the Second Battle of Ypres in 1915, with the Germans in occupation of these positions until the Battle of Messines in June 1917. This observation bunker, apparently built into the site of the German front line at what the British called Immovable Trench.

The bunker is in good condition, shows signs of battle damage, but is somewhat overgrown. It is just off the path up to the Caterpillar Crater on ground now owned by the local authorities.