There are certain subjects which warrant treatment of the subject even if they do not fit neatly into the envelope of the IB Subject Guide.  One such example of this is the collision of the SS Mont Blanc and the SS Imo on 6 December 1917.

The Mont Blanc was a French ship loaded with ammunition in New York City that was sent up to Halifax, Nova Scotia, to join an convoy  across the Atlantic. At dawn on 6 December it headed into the harbor without displaying the red flag that would let everyone in the harbor know that it was bearing dangerous cargo.  At the same time the Imo, a Norwegian ship that had been delayed, began its exodus from the harbor, unaware of the danger that a close encounter with the Mont Blanc would cause.  The two ships collided, and the Mont Blanc’s captain abandoned ship and it headed towards the wharf, which was heavily populated.

The Mont Blanc was on fire, and sporadic explosions of the ammunition was viewed with amusement and awe by those on the shoreline, unaware of the potential danger in the ship.  20 minutes after the collision, fires ignited nearly 3,000 tons of munitions, leading to the largest man-made explosion in human history prior to the detonation of the first atom bomb in 1945.  The ship itself was vaporized, and one square mile of the the harbor was destroyed instantaneously, resulting in the deaths of over 2000 people—or 12% of Halifax’s population.  There was a shockwave that created a tsunami, drowning those on the shoreline, and shattered glass windows, leading to nearly 600 eye injuries.  The city had to rebuild.

In the midst of the Great War, the Halifax explosion lost its gravitas.  Other provinces and Allies provided assistance quickly that helped rebuild the community, but this was one of many tragedies, and the event was not addressed publicly, not even in Halifax itself, until 1967.  This has changed, however.  Interest in the subject was renewed in the 1980s, and as the explosion drew the interest of historians, individuals began to share photos and memoirs culminating in some fairly extensive exhibits that commemorate the centennial anniversary.

The Maritime Museum of the Atlantic has an online exhibit dedicated to it at, as does the Library and Archives Canada (; and the University of Viriginia provides a medical history of the effect of the explosion at

Many teachers address the Halifax Explosion, but students often ask how this will help them on their IB exams.  I have given this considerable thought, and I am still not entirely sure.

Two potential ways to use this information:

  1.  World History Topic 11 is 20th century wars, and the explanatory paragraph starts with, ‘This topic focuses on the causes, practice and effects of war in the 20th century’ (History Guide, page 35).  Students can be asked about the mobilization of economic and human resources within the topic ‘practices of war and their impact’.
  2. With the Americas section 10, one of the bullets is ‘Impact of the First World War on any two countries of the Americas: economic, political, social and foreign policies’ (page 51).

These may be places where the material can be used, if the right question arises, but there is no guarantee that such a specific example can be used with certainty.  If a question appears that invites candidates to Discuss the impact of practices of war on the civilian population of one country. this could provide one concrete example, but that is a stretch.

In the end, this is one of many historical events that are worth studying, analyzing and considering but may not fit into the parameters of the examination frameworks.  It is a story that you will remember even if you don’t remember the reasons why the Allies defeated the Central Powers – just as you will remember the death of Rasputin vividly while forgetting his role in the February Revolution.