Balloon view of the bombardment of Roclincourt, 23 September 1915. This photo shows how sparse a bombardment could beespecially in 1915, with the shell shortage looming over all plansand how important aerial observation was. In terrain this flat, ground-level observation was nearly useless, and a house or tree used as an observation post would soon have been bombarded.
Source: IWM photo Q42236.