5921647 An aerial view of the trenches, 2 April 1916 (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: 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.); by National Army Museum ; out of copyright.