the halifax explosion took place on december 6, 1917 when the ss "mont-blanc", a french cargo ship loaded with explosives collided with the ss "imo", a norwegian ship in the harbour in halifax, nova scotia, canada. 1,782 people were killed and over 9,000 people were injured. this was the largest man-made explosion in history until july 1945 when the first atomic bomb blew up. it is still the largest accidental explosion in history. people were said to here it from over 100km away!