December 1917 saw one of the greatest disasters in Canadian history, when the , a French cargo ship carrying munitions, collided with the Belgian Relief vessel in "The Narrows" between upper Halifax Harbour and Bedford Basin. The resulting explosion, the Halifax Explosion, devastated the Richmond District of Halifax, killing approximately 2,000 people and injuring nearly 9,000 others. The blast was the largest artificial explosion before the development of nuclear weapons. Significant aid came from Boston, strengthening the bond between the two coastal cities.