Among the most accomplished and well known of the world's deep-sea explorers, Robert Ballard is best known for his historic discoveries of hydrothermal vents, the sunken R.M.S. Titanic, the German battleship Bismarck, and numerous other contemporary and ancient shipwrecks around the world. During his long career he has conducted more than 120 deep-sea expeditions using the latest in exploration technology, and he is a pioneer in the early use of deep-diving submarines.