Decades after the Titanic sank into the Atlantic, the dream of investigating the wreckage was finally realized by undersea geologist Dr. Robert D. Ballard. Only one camera crew was permitted to join his historic expedition in 1986. In this remarkable program, high-tech cameras attached to submersibles take us to the frigid world two and a half miles below the ocean’s surface. Spectacular colour photography illuminates the ship’s once luxurious interior.

• Documentary