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An explosion caused by an accidental collision between two merchant ships, one filled with explosives for the war, occurs in Halifax Harbour, resulting in 2000 people dead and 9000 injured.
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Alberta and Saskatchewan are partitioned out of the Northwest Territories to become the eighth and ninth provinces of Canada.
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Royal Canadian Navy is established.
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The United Kingdom declares war on Germany, bringing Canada into the First World War.
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The four divisions of the Canadian Expeditionary Force fight together for the first time in the Battle of Vimy Ridge, which becomes celebrated as a national symbol of achievement and sacrifice and a formative milestone in the development of Canada's national identity.
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Women gain the right to vote in federal elections.
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Canadian Air Force (after 1920, Royal Canadian Air Force) is established.
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Canada sends a delegation to the Paris Peace Talks, the conference resolving war issues. Canada signs the Versailles treaty as part of the British Empire, with parliament's approval.
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Canada is admitted as a full member of the League of Nations, independently of Britain. It joins the League Council (governing board) in 1927. Canada plays a minor role and opposes sanctions or military action by the League. The League is virtually defunct by 1939.
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A constitutional crisis, known as the King-Byng Affair, is precipitated when Governor General Byng refused Prime Minister King's request to dissolve parliament and call an election, instead asking opposition leader Meighen to form a government, which in turn was quickly defeated. King framed the dispute as one of the United Kingdom, represented by the Governor General, interfering with Canadian affairs. Consequently, the affair played a role in the Balfour Declaration of 1926, in which each Domi
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Canada appoints Vincent Massey as its first fully accredited envoy to a foreign capital.
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Great Depression in Canada begins, resulting in widespread poverty and unemployment for the next decade.
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Canada, with its parliament's support, enters the Second World War by declaring war on Germany, one week after Britain and France.
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Canada joins United Nations, seeking to play a world role as a "middle power", with interest in the UN Charter and in relief agencies.
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Newfoundland enters Confederation as the tenth province following a pair of contentious referenda on whether the island should remain a British Crown Colony, become fully independent, or join Canada.
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Newfoundland enters Confederation as the tenth province following a pair of contentious referenda on whether the island should remain a British Crown Colony, become fully independent, or join Canada.
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The Saint Lawrence Seaway, a joint project between Canada and the United States, is officially opened.
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The Statute of Westminster 1931 is enacted in the United Kingdom, officially ending the power of the British parliament to pass and nullify laws in a Dominion without the Dominion's request and consent. The statute formally recognized the de facto independence attained by Canada following the First World War.