One hundred years ago today, the Titanic launched. It was designed to carry 3511 passengers and was supposed to be "unsinkable" with lifeboats for less than a third. It was first dropped into the waters in Belfast on May 31, 1911. She got the traditional shakedown and then there was that quick stop in Southhampton on the way to New York and then an unscheduled stop at the bottom of the sea just after midnight on 15 April, 1912, after hitting an iceberg. Less than a third of the people on board survived. The BBC's Mark Simpson reports from Belfast on the anniversary of the launch.