World War II: <a href="https://en.wikipedia.org/wiki/Operation_Spring" id="mwAVA" rel="mw:WikiLink" title="Operation Spring">Operation Spring</a> is one of the bloodiest days for the <a href="https://en.wikipedia.org/wiki/First_Canadian_Army" id="mwAVE" rel="mw:WikiLink" title="First Canadian Army">First Canadian Army</a> during the war.