21.—Observation-post near the Church of Clercken.

Clercken Ridge was very precious to the enemy to whom it gave the opportunity to establish a lot of natural observation-posts which had not the vulnerability of the confined kite balloons and which assured more stability to the observation. Many of these posts were destroyed during the war, especially by the destructive fires which preceded the great offensive in Flanders on the 28^th of September 1918. Others, such as the mill of Clercken, are already rebuilt, so offer no longer any historical interest.

German observation-post near the church of Clercken.
Sketch showing the directions of the villages seen from this observation-post.

However the one which is situated near the church of Clercken, and still exists in the same state as when abandoned by the Germans (see sketch), shows how easily the enemy could see into our lines, in spite of all the efforts made by the Belgian Army to counteract their observations, such as: diverse dissimulations, plantations of all kinds, artificial masks in linen, sandbags, reeds and straw, etc....