5923015 ?North Country troops bomb Hun machine-gunners out of their lairs in Polygon Wood, September 1917? (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: ?North Country troops bomb Hun machine-gunners out of their lairs in Polygon Wood, September 1917?. Stereoscopic photograph, World War One, Western Front (1914-1918), 1917. On 26 September 1917 five British and two Australian divisions attacked the German positions at Polygon Wood to the east of Ypres. The assault was one of General Herbert Plumer?s so called ?bite and hold? operations, attacks with limited objectives. An area of the German line would be heavily shelled and then attacked in strength. The advancing troops would stop once they had penetrated 1,500 yards into the enemy trenches. At this point they would dig in. When the German counter-attack was launched, instead of finding a mass of exhausted and disorganised men at the limit of their advance, they would find a well organised defensive line still in range of supporting artillery. The Polygon Wood operation was a success with nearly all objectives being taken. The Germans launched several counter-attacks but these were thwarted by the heavy defensive artillery barrages. A feature of the fighting, which lasted until 3 October 1917, was the fierce mopping-up actions to clear German defenders from dugouts and pillboxes untouched by these barrages. From a collection of 101 stereoscopic photographs entitled ?The Great War?.); by National Army Museum .