Dark Waters (Once Upon a Time) is to take Snow's heart. The Land of Untold Stories is revealed to be the Mysterious Island from the book as the same name. The "Nautilus" is based on the submarine from "Twenty Thousand Leagues Under the Sea". Captain Nemo based on the protagonist from Jules Verne's novel "Twenty Thousand Leagues Under the Sea". Hook refers to the giant squid that attacks him as a kraken. The kraken is a legendary sea monster of giant size that is said to dwell off the coasts of Norway and Greenland. The episode posted its lowest numbers so far in the series, as
20,000 Leagues Under the Sea: Submarine Voyage of realism. Eight submarines painted in grey took guests through the attraction, which took place in a lagoon visible from Tomorrowland and a large show building hidden behind two waterfalls. It became extremely popular with guests, and Walt Disney Imagineering consequently planned for more elaborate version for the forthcoming Florida Project concept, which would become Walt Disney World. One of the signature pieces of 20,000 Leagues Under The Sea was the fleet of passenger vehicles, adapted for theme park use from Harper Goff's Nautilus design for the 1954 Disney live-action version by Disney Imagineer George McGinnis. The basic hulls were