North Ireland's former first minister and peace negotiator Martin McGuinness died at age 66. McGuinness, who was diagnosed with a rare heart disease in December, passed away early Tuesday morning. McGuinness was a former Irish Republican Army commander who later led the country toward reconciliation with Britain. As a young IRA fighter, McGuinness made it his mission to fight for the Catholic minority against the pro-British protestants in North Ireland. In 1998, McGuinness negotiated a peace deal and shook hands with the Queen as a symbol of resolution.