Aerial view of a trench system. One of a series of British aerial reconnaissance photographs recording the positions of trenches on the Western Front during the First World War. An intricate trench system, probably British, zig-zags its way across a patchwork of fields. An original caption indicates no man's land as the area in the top right hand corner, bordered by dark lines of barbed wire protecting the front line to the south. Nord-Pas de Calais or Picardie, France, 17 February 1918., Nord-P