An aerial view of the trenches, 2 April 1916

Photograph, World War One, Western Front (1914-1918), 1916.

As this photograph of a sector of the German line shows, the front line trenches were part of a complex design. Each was backed-up by second and third lines: 'support' and 'reserve' trenches. Communication trenches linked them all together. The support and reserve trenches were lined with underground shelters or dugouts which were used as protection from enemy fire and the weather.

From a collection of official photographs.