A German observation post near La Bassée, 1915

Photograph, World War One, Western Front (1914-1918), 1915.

Observation posts were used to watch the enemy front and direct artillery fire on to targets. They were usually situated ahead of the gun positions and camouflaged to avoid detection. Sometimes a post would be hidden out in no-man's-land in a ruined building or damaged tree.

From an album of 284 photographs compiled by Second Lieutenant R T Cooper.