1-217-679 - The Print Collector/Heritage Images

A French sapper digging a tunnel to place a mine under the enemy lines, France, 1915. The placing of huge explosive mines in tunnels beneath enemy trenches became a common tactic on the Western Front during World War I. The work was difficult, dangerous and claustrophobic, with the risk of cave-ins and of encountering enemy tunnellers, leading to hand to hand fighting underground. British sappers spent two years placing 21 mines beneath the German lines at Messines Ridge near Ypres. At the opening of the Third Battle of Ypres (Paschendaele) in 1917 the mines were simultaneously detonated (only 19 exploded - one remains unaccounted for and theoretically still live today) causing 10,000 German casualties.