The blasts killed around 10,000 men, devastated German front lines, and was so loud it was heard in London.
Though an extreme example, what happened at Messines illustrates perfectly why British commanders held their tunnellers in such high regard. They employed entire companies of men – often miners – to dig tunnels under no-man’s land, place mines below enemy positions and, if all went to plan, blow them to smithereens.
Yet though tunnellers could cause spectacular damage to enemy trenches, theirs was a terrifying job. They worked in cramped, dark conditions for days – at risk of being permanently entombed by collapsing tunnels or detection by enemy tunnellers listening out for them in the dark.