First, perhaps the most important discovery in underwater exploration was Dr. Robert Ballard's 1985 detection of the wreckage of the "unsinkable" R.M.S. Titanic on the Atlantic floor. The National Geographic documentary "Secrets of the Titanic" includes an exclusive interview with Ballard and glimpses of the luxury liner's remains. Next, "Save the Titanic with Bob Ballard" (2012) by reviewing how the physical integrity of the wreck has been threatened by multiple salvage operations and the natural processes of underwater decay. 100 min. total. Widescreen (Enhanced); Soundtrack: English Dolby Digital 5.1; bonus programs; photo gallery.