4 Reconnaissance Photographs (Northern France / Belgium) (i.) June 1917 - Pilckem area - indicates key features including trenches. (ii.) 21st July 1917 - Unknown area (N. France / Belgium?) - shows network of trenches. (iii.) 24th April 1917 - Unknown area (N. France / Belgium?) - shows network of trenches, river with makeshift bridges. (iv.) 17th June 1917 - Pilckem area - displays key features, including trenches. 1917