20,000 Leagues Under the Sea (1954)

Disney-made adventure based closely on the original Jules Verne story of a 'sea monster' which causes chaos amongst 19th-century San Francisco mariners. When a government warship investigates, the 'monster' attacks, leaving just three survivors who are picked up by the creature - which turns out to be a submarine captained by a demented fanatic whose masterplan is to establish an undersea nation.