"Twenty Thousand Leagues under the Sea" by Jules Verne is a science fiction adventure novel serialized from 1869 to 1870. When ships worldwide report encounters with a mysterious sea monster, an American expedition sets out to destroy it. Professor Aronnax, harpooner Ned Land, and servant Conseil discover the creature is actually a futuristic submarine commanded by the enigmatic Captain Nemo. Held captive aboard the Nautilus, they embark on an extraordinary underwater journey, witnessing marvels and mysteries beneath the waves while uncovering their captor's dark past.