17th May 1718: On this date Edinburgh's Greyfriars Kirk was accidentally blown up by gunpowder. Not quite the Gunpowder Plot of 1605 on London's House of Lords but instead just a simple accident.
Edinburgh Town Council at that time stored their gunpowder in a small tower at the west end of the church. "This was surely asking for trouble!" I hear you loudly shout, and you'd be right. The west end of the church was obliterated, and a new west wall was built.