‘The year 1866 was marked by a strange incident, an unexplained and inexplicable phenomenon … which disturbed the maritime population and exciting the public mind in the interior of continents.’ Thus, began Jules Verne's classic science fiction adventure Twenty Thousand Leagues Under the Sea. Published in 1870, the novel began with reports of an unknown monster sinking a number of ships. Verne's description of the sightings, the rumours and the debates surrounding the creature's existence accurately reflected the sea serpent periodical literature of the time.

Although sea serpents are most often associated with myth and legend, in the nineteenth century they achieved a margin of scientific legitimacy that they never had before or since, capturing the imagination of a public trying to make sense of the vast new developments in science. The discovery of fossils, particularly dinosaurs, provided tangible evidence for the existence of creatures which had been regarded as belonging to the realm of the fantastic. As paleontologists discovered plesiosaurs and ichthyosaurs, a dramatic increase in sightings of sea serpents also occurred.