Members of the Princess Patricia Light Infantry leave Victoria before setting sail for France in this image from November 20, 1939. The Second World War officially began on September 1, 1939, with the German invasion of Poland. Britain and France declared war on the Nazi Third Reich two days later. On September 10, 1939, Canada entered the conflict, the country's first independent declaration of war, marking   the beginning of our participation in the bloodiest and most brutal conflict in history.