McCrae fought in the Second Battle of Ypres in the Flanders region of Belgium, where the German army launched one of the first chemical attacks in the history of war. They attacked French positions north of the Canadians with chlorine gas on April 22, 1915, but were unable to break through the Canadian line, which held for over two weeks. In a letter written to his mother, McCrae described the battle as a "nightmare",
McCrae fought in the Second Battle of Ypres in the Flanders region of Belgium, where the German army launched one of the first chemical attacks in the history of war. They attacked French positions north of the Canadians with chlorine gas on April 22, 1915, but were unable to break through the Canadian line, which held for over two weeks. In a letter written to his mother, McCrae described the battle as a "nightmare"