From 1916 onwards, the Allies attempted to undermine the German positions on the Wijtschate-Mesen ridge. The Germans knew this and in response dug thirty or so vertical shafts, which were connected with horizontal tunnels deep underground. This was their way of trying to find the Allied mines. The Dietrich shaft in the Kampagnebos (Campagne Wood) is one of these German shafts. It is lined with concrete blocks and is about 25 metres deep. At its bottom, a tunnel once ran about 180 metres in the direction of the old British lines.
The Dietrich Shaft can be reached by the car track to the Kampagnebos (Campagne wood). Follow the wood path and you will find the Dietrich Shaft about 100m on your left.