The two photographs on Page 20 were taken by an RE8 of 6 Squadron, part of the squadron's aerial reconnaissance operations over the Western Front during WW1.

 

The photographs were were taken over Ravine Wood, Denys Wood and Pheasant Wood, as defined by mapping coordinates 28. O. 9. D. The first photograph was taken on the 23rd March 1917 and the second on the 3rd June 1917, 4 days before 19 mines were detonated beneath the German lines along the Messines ridge at the start of the Battle of Messines