After the sinking of the Titanic in April 1912, her sister ship, the Britannic, ultimately suffered the fate. The Britannic sank in 1916 due to an explosion caused by an underwater mine. In the wake of the Titanic disaster, Britannic was re-engineered to be even stronger. And yet she sank in just 55 minutes - three times faster than Titanic. It's one of Britain's greatest untol...