Twenty Thousand Leagues Under the Seas in the context of Michael Strogoff

Sea monsters are beings from folklore believed to dwell in the sea and are often imagined to be of immense size. Marine monsters can take many forms, including sea dragons, sea serpents, or tentacled beasts. They can be slimy and scaly and are often pictured threatening ships or spouting jets of water. The definition of a "monster" is subjective; further, some sea monsters may have been based on scientifically accepted creatures, such as whales and types of giant and colossal squid.

Jules Gabriel Verne (/vɜːrn/; French: [ʒyl ɡabʁijɛl vɛʁn]; 8 February 1828 – 24 March 1905) was a French novelist, poet, and playwright.

His collaboration with the publisher Pierre-Jules Hetzel led to the creation of the Voyages extraordinaires, a series of bestselling adventure novels including Journey to the Center of the Earth (1864), Twenty Thousand Leagues Under the Seas (1870), and Around the World in Eighty Days (1872). His novels are generally set in the second half of the 19th century, taking into account contemporary scientific knowledge and the technological advances of the time.

The literary genre of science fiction is diverse, and its exact definition remains a contested question among both scholars and devotees. This lack of consensus is reflected in debates about the genre's history, particularly over determining its exact origins. There are two broad camps of thought, one that identifies the genre's roots in early fantastical works such as the Sumerian Epic of Gilgamesh (earliest Sumerian text versions c. 2150–2000 BCE). A second approach argues that science fiction only became possible sometime between the 17th and early 19th centuries, following the Scientific Revolution and major discoveries in astronomy, physics, and mathematics.

Science fiction developed and boomed in the 20th century, as the deep integration of science and inventions into daily life encouraged a greater interest in literature that explores the relationship between technology, society, and the individual. Scholar Robert Scholes calls the history of science fiction "the history of humanity's changing attitudes toward space and time ... the history of our growing understanding of the universe and the position of our species in that universe". In recent decades, the genre has diversified and become firmly established as a major influence on global culture and thought.

Humans have made multiple uses of molluscs, including as food, and they feature in art and in literature.

Useful interactions with molluscs range from their use as food, where species as diverse as snails and squid are eaten in many countries, to the employment of molluscs as shell money and to make dyestuffs and musical instruments, for personal adornment with seashells, pearls, or mother-of-pearl, as items to be collected, as fictionalised sea monsters, and as raw materials for craft items such as Sailor's Valentines. Some bivalves are used as bioindicators to monitor the health of marine and freshwater environments.

Captain Nemo (/ˈneɪmoʊ/; also known as Prince Dakkar) is a character created by the French novelist Jules Verne (1828–1905). Nemo appears in two of Verne's science-fiction books, Twenty Thousand Leagues Under the Seas (1870) and The Mysterious Island (1875). He also makes a brief appearance in a play written by Verne with the collaboration of Adolphe d'Ennery, Journey Through the Impossible (1882).

Nemo is a mysterious figure. Though of unknown nationality in the first book, he is described as the son of an Indian raja in the second book. A scientific visionary, he roams the depths of the seas in his submarine, the Nautilus, which was assembled from parts manufactured in several different countries, then shipped to a cover address. The captain is consumed by a hunger for vengeance and hatred of imperialism; Verne included references to anti-imperialist uprisings, including the Kościuszko Uprising and Indian Rebellion of 1857, in the various backstories of Nemo.

Nautilus is the fictional submarine belonging to Captain Nemo featured in Jules Verne's novels Twenty Thousand Leagues Under the Seas (1870) and The Mysterious Island (1875).

The Voyages extraordinaires (French: [vwajaʒ ɛkstʁaɔʁdinɛʁ]; lit. 'Extraordinary Voyages' or 'Amazing Journeys') is a collection or sequence of novels and short stories by the French writer Jules Verne. The cycle features some of Verne's best known titles, such as Journey to the Center of the Earth, From the Earth to the Moon, Twenty Thousand Leagues Under the Seas, Around the World in Eighty Days and The Mysterious Island.

Fifty-four of these novels were originally published between 1863 and 1905, during the author's lifetime, and eight additional novels were published posthumously. The posthumous novels were published under Jules Verne's name, but had been extensively altered or, in one case, completely written by his son Michel Verne.

Daniel Frederik Eschricht (18 March 1798 – 22 February 1863) was a Danish zoologist, physiologist, and anatomist known as an authority on whales. He was born in Copenhagen, and studied medicine at Frederiks Hospital, graduating in 1822. He was a student of François Magendie in Paris from 1824-1825, composing a thesis on cranial nerves, after which he studied with prominent European naturalists and anatomists, including Georges Cuvier. He joined the University of Copenhagen in 1829, becoming Professor of Anatomy and Physiology in 1836. The gray whale genus Eschrichtius was named for him a year after his death. In 1861, Eschricht dissected an orca and found thirteen common porpoises and fourteen seals inside. Jules Verne referred to the incident in the Sargasso chapter of his 1870 novel Twenty Thousand Leagues Under the Seas.

He was elected as a member of the American Philosophical Society in 1863.