On this date, in 1917, nineteen enormous British mines were detonated at the Battle of Messines.
The detonations left 10,000 German soldiers dead.
By some accounts the explosions were the largest non nuclear explosions ever. The blast could be heard as far away as Dublin, Ireland.
The ensuing battle lasted for a week and like most World War One battles the results are debated. The British Empire forces did advance. Contemporary German accounts regarded the battle as a devastating German defeat.