5921651 Wrecked windmill observation post, 23 October 1917 (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: Wrecked windmill observation post, 23 October 1917. Photograph, World War One, Western Front (1914-1918), 1917. Located at Beaurains, this windmill was lined with reinforced concrete and used as an observation post. It was destroyed by British artillery during the Battle of Arras. From an album of 76 official photographs, 1916-1917.); by National Army Museum ; out of copyright.