Maritime archaeologists and historians go in search of the biggest wrecks ever sunk beneath the seas. New scientific data combines with cutting-edge computer graphics to drain the oceans to investigate the world's most awe-inspiring wrecks. Explored are: HMHS Britannic, sunk in 1916 by a WWI German naval mine near the Greek island of Kea; Amoco Cadiz, a supertanker that ran aground/broke up during a gale off Brittany, France in 1978 (worst oil spill in history); MV Derbyshire, a bulk carrier of iron ore overwhelmed during Typhoon Orchid, south of Japan in 1980; and SS El Faro, a container ship lost with all hands off the Bahamas during Hurricane Joaquin in 2015.