At the start of the Battle of Messines (7–14 June 1917) during the First World War, underground explosive charges were detonated by the British Second Army (General Sir Herbert Plumer) beneath the forward position of the German 4th Army near the village of Mesen (Messines in French, historically used in English), in Belgian West Flanders. The mines, secretly planted by British tunnelling units, created 19 large craters and killed approximately 10,000 German soldiers. Their joint explosion ranks among the largest non-nuclear explosions of all time.