Relive the terrible fate of an historic ship and join one of the most thrilling deep-water expeditions of all time in this mesmerizing special presentation. HMHS Britannic, the largest and grandest of the Olympic Class cruisers, sister ship to the ill-fated Titanic, was launched just six months before the outbreak of WWI and was soon pressed into service as a floating hospital. On November 21, 1916, while steaming through the Kea Channel in the Aegean Sea, an explosion ripped through the Britannic and in less than an hour, the ship sank beneath the waves, taking the lives of 30 men with it. Whether it was a German mine or submarine torpedo that caused the blast, a bigger mystery remains: why and how did this giant ship sink so fast?. From deadly chambers to decades-old mysteries, join wreck divers John Chatterton and Richie Kohler as they lead an exhilarating expedition to unravel the mystery of the Britannic's final hour.