At precisely 9:06 on December 6, 1917, the worst man-made explosion ever [before the atomic bomb on Hiroshima] tore through Halifax, claiming 2,000 lives.

The Great War had brought prosperity to Halifax. The harbour bustled with convoys of men and materials bound for Europe.

Outside the harbour sat the French steamship Mont Blanc awaiting morning access to the harbour and official clearance. Four days earlier his freighter had been loaded with tons of picric acid, TNT, gun cotton and benzol. The Mont Blanc was a floating bomb.

At 7:30 a.m., on December 6, the Mont Blanc began its slow entry into the harbour just as the Imo pulled up anchor. Forced to the wrong side of the channel by a steamer and tugboat, the Imo continued its improper course in direct line with the incoming Mont Blanc. There was a confusion of whistle blasts, misunderstood signals and, at 8:45 a.m., a disastrous collision.

It was the worst catastrophe in Canadian history.