The actual undersea footage was shot in the Bahamas in the same location that was used for the silent 20,000 Leagues Under the Sea (1916).

Richard Fleischer was surprised at being considered for the director's chair for this film, as he was the son of Disney's biggest competitor, Max Fleischer. He approached Walt Disney to inquire if Disney knew who he was. Disney told him that he was well aware of who he was and hired him because he thought he was the best man for the job. Richard Fleischer also asked his father if he minded having his son working for his rival but Max Fleischer made no objection and even asked Richard to tell Disney that he thought he had made an excellent choice for his director!

Peter Lorre claimed that the giant squid got the role that was usually reserved for him.

Actors portraying the cannibals chasing Ned Land painted humorous messages on their foreheads (not legible on-screen). In particular, one actor wrote "Eat at Joe's" while another actor behind him wrote "I ate Joe".

This was Walt Disney's first feature using the new CinemaScope process, as well as one of the first productions outside of 20th Century-Fox use that anamorphic wide screen process. At the time, Bausch & Lomb had not been able to manufacture enough anamorphic lenses to meet the demand, so the Disney studios needed to lease the single available CinemaScope lens from 20th Century-Fox. This prevented multiple units from shooting at the same time, which not only contributed to the lengthy production schedule, but also--since Disney wanted the best possible value for the CinemaScope lens rental--explains the almost complete absence of close-up shots in the movie.

The climactic squid battle on the Nautilus was originally shot with a serene sunset and a calm sea. Director Richard Fleischer was troubled by the look of it because the cams and gears that operated the squid could easily be seen, making it look obviously fake. Walt Disney visited the set one day and Fleischer told him about the problem. Disney came up with the idea of having the squid battle take place during a fierce storm (another story is that it was actually screenwriter Earl Felton who came up with the idea). The scene was reshot that way and is considered by many to be the highlight of the film.

Cast members carried herring in their pockets to reward Esmerelda the seal after their scenes with her. Director Richard Fleischer was especially amused when the distinguished James Mason had to reach into his pocket after a shot. Fleischer said the cast smelled like the Fulton Fish Market.

In 1969, Captain Nemo's pipe organ, which had been on display in Disneyland, was redressed and now resides in the ballroom of Disneyland's Haunted Mansion. A duplicate was constructed for the ballroom of Walt Disney World's Magic Kingdom Haunted Mansion, which opened in 1971, and over a decade later another duplicate was built for Tokyo Disneyland.

This was the first new full-length Disney film released by Buena Vista, Disney's new in-house distributor. Previous Disney films had been released by RKO, and re-releases of old Disney films were handled by Buena Vista from 1954 onwards.

Until the late 1960s, many of the sets representing the interior of the Nautilus were used as an attraction at Disneyland. This included the chart room, the salon, with organ, and one of the observation windows. The squid from the movie was fastened over the observation window and was animated so that the beak would emerge, snap several times, and then retract. When the building housing the "20,000 Leagues" display was needed for a newer attraction, the sets were removed and many were destroyed.

The skiff was made of wood, painted to look like metal, and had to be weighted with sandbags to look heavy in the water. When towing it to the cannibals' island, the crew took the sandbags out to make their job easier, and they forgot to put them back in. When filming the scene where Ned and Conseil get in the boat to row away from the cannibals, Kirk Douglas expected the boat to be low in the water. He didn't lower the oars far enough to catch the water, and when he started to row, he fell on his back. Director Richard Fleischer thought the shot was so funny he left it in the film. When Ned starts to row, he clearly tips back, and his legs shoot up in the air.

This production was so large that Disney had to use facilities at other studios. This included Universal International (exterior sets redressed for the opening scenes) and 20th Century Fox (large exterior tank for the larger models).

One of the models of the Nautilus created by Harper Goff was a "squeezed" version which could be filmed with a standard lens and still look normal when projected in Cinemascope.

In addition to his many contributions as the production designer, Harper Goff also taught Kirk Douglas to play the guitar for the "Whale of a Tale" number.

When the "Nautilus" rams a ship and we see how it sinks down through the water, some of the bubble-streams are animated to hide the wires that support the ship-model.

Walt Disney originally considered making this film as an animated feature; the detailed pre-production sketches by artist Harper Goff, as well as Goff's enthusiastic suggestion that it be done as live action feature, convinced him otherwise.

During the underwater shooting of the Treasure Chest scene, an unscripted nurse shark approached Ned, Conseil and the camera crew. All underwater personnel, as seen in Disney's Wonderful World of Color Sunday Night television episode highlighting the upcoming film, attempted to warn the shark off, but the interruption was considered so exciting that portions were left in the final film.

The world's first functional replica of Captain Nemo's diving helmet, built by Pat Regan of Vulcania Submarine, Hawaii, is on display in the Florida Keys History of Diving Museum in Islamorada, along with items from the film. He also restored an authentic Disney "Crowntop" crewman's diving helmet to operational condition and dived it in Hawaii, 2008; making it the only piece of 20,000 Leagues diving gear returned to service since 1954.

No fishing boat would (or will) carry bananas, considered bad luck by deep water fishermen.

The design of the Nautilus was heavily modified to make it appealing for the audience. In the original novel, Nemo's ship is rather plain, described as a long cigar with its hull plates superimposed, so they resemble the scales of a fish. The helmsman and reflector booths are retractable, and the vessel only raises 3 ft. over the water when at the surface. Also, it has no windows or exterior features, except the main hall panoramic window, which is usually kept concealed under the hull plates.

Kirk Douglas was taught how to play the guitar by Harper Goff. In supplemental material on the DVD it was revealed that he learned quickly and invented the "throw the guitar and pull it back" trick used in the "Whale Of A Tale" sequence all by himself.

When Disney executives saw some underwater scenes their photographers had filmed in the new VistaVision wide-screen format, they decided to make "20,000 Leagues Under the Sea" and incorporate some of the shots in it.

During his 'Whale of a Tale' tune, two of the girls Ned sings about are named 'Mermaid Minnie' and 'Typhoon Tessie'. Minnie and Tessie were the two girls on his arms at the beginning of the film - you can hear him shout their names at one point during the street brawl.

A league is considered to be 3 nautical miles at sea (a nautical mile is about 1.15 miles). Therefore if they traveled 20,000 leagues they would have traveled about 68,350 miles, enough to circle the Earth almost two and one half times.

According to Kirk Douglas in his autobiography, "Ragman's Son", the scene at the beginning of the film where Ned Land strolls up (with a beautiful girl on each arm) to the lecturing sailor - and the ensuing fight - was written into the film at his request. At the time this film was shot, Douglas was in the prime of his career and very concerned about promoting and preserving his reputation with the movie-going public as both a dashing ladies man and a "macho" actor known for tough, physical roles that showcased his image as an action hero (fight scenes and so forth). When he first read the first draft script for this film, he was somewhat disappointed to find that his character Ned Land made no appearances with any women whatsoever, had no real rousing fight scenes, other than the battle with the squid, and spent most of the movie talking instead of being in action. Having expressed these concerns both to Walt Disney and director Richard Fleischer, the San Francisco street scene at the beginning of the film - featuring his character involved with two beautiful women in addition a rousing action/fight scene - was added especially for him (in at least two later films Douglas also made sure his character would be seen with two beautiful women at the same time and be involved in plenty of rough & tumble action: The Vikings (1958) [also directed by Fleischer] and The War Wagon (1967).

In the supplemental material on the DVD mention is made that there was great camaraderie between most of the actors with the exception of Paul Lukas. Mr. Lukas held himself aloof seeming to consider himself too sophisticated to mingle. It may have also been that, because of his age, he was having trouble remembering his lines and was embarrassed.

Stage 3 and its tank were built at the Disney studio for the production of this film.

Gregory Peck auditioned for the role of Captain Nemo.

The fictional Disney Nautilus actually exists as a real submarine, and it was built by a fan! Pat Regan's Nautilus Minisub was the World's first "real" Disney Nautilus submarine (manned, free-roving, pressure hull-type submersible boat) in any scale: designed and handcrafted in steel by one man working alone in a modest backyard shop in California between 1986 and 1991; acknowledged in writing by Corporate Disney as a visually accurate depiction of the Disney Nautilus in 1992. In 1993, Regan moved to Hawaii where he became prolific in recreating and diving Disney's unique underwater technologies, including the 20,000 Leagues diving apparatus. The submarine is presently being refurbished for continued operations in the Pacific.

One of the models of the Nautilus used for filming was on display at Walt Disney World's EPCOT Center's attraction, "The Living Seas" until the display was remodeled.

Sections of the film were photographed on location in Jamaica and the Bahamas, by director Richard Fleischer and a crew of over 400 technicians.

In the scene where Kirk Douglas arrives at the Nautilus on a lifeboat that lies upside-down in the water, a diver under the boat holds it to keep it steady.

The interiors of the Nautilus were designed by Roland E. Hill Sr., who subsequently designed the Disneyland "Sleeping Beauty's Castle."

This was the one of the first Disney films shown in a two-hour time slot on television (although very slightly edited). Most previous telecasts of Disney films, all shown on the anthology series Disneyland (1954) (aka "The Wonderful World of Color" and "The Wonderful World of Disney") had either featured the films edited down to fit a one-hour time slot or broken them up into two or more one-hour segments shown over a period of several weeks.

The whole movie, except for the scenes where Ned Land and Conseil go ashore at New Guinea and meet the cannibals, and most of the underwater scenes with the divers, were filmed at the Disney Studio.

Walt Disney briefly considered English actor Ralph Richardson for the role of Captain Nemo.

Richard Fleischer was the son of Max Fleischer, head of a rival animation studio. Richard was reluctant at first to take the job until his father encouraged him to do so, sending with him his compliments to Walt Disney on his taste in directors.

Although Percy Helton was billed in the opening credits, his role (as a coach driver) was almost entirely eliminated; in the release version, he appears in just two shots and has only one line: "Yes, sir."

In the opening credits, the title banner does not have a comma between the first and second zeroes ("20000 Leagues Under the Sea"), although a comma does appear on the poster and all related print advertisements.

Kirk Douglas's salary was $175,000., the most that Walt Disney had paid to any actor at that stage.

In 1984, Dino De Laurentiis took out a full page ad in Variety announcing a remake. George Macdonald Fraser was hired to adapt the screenplay, and Richard Lester was approached to direct. However due to a string of flops, De Laurentiis was unable to find funding.

Kirk Douglas initially declined to appear in the film, fearing it would damage his reputation as both a ladies' man and a tough guy. Walt Disney had the script re-written so that he would be introduced in the company of two attractive women, and immediately get into a fight. Douglas then agreed to be in it.

Charles Boyer was originally considered for the role of Professor Arronax. He had to turn down the role due to prior commitments.

Following the opening credits, the film commences with Jules Verne's novel opening up with 'Chapter 1 Alarming Rumours !'. The book title is shown as Twenty Thousand Leagues Under the Sea as opposed to 20000 Leagues Under the Sea.

Average Shot Length (ASL) = 9 seconds

CASTLE THUNDER: Right at the start of the storm sequence with the giant squid.

Her role as one of Ned's female companions was the feature film debut of Laurie Mitchell.

Included among the American Film Institute's 1998 list of the 400 movies nominated for the Top 100 Greatest American Movies.

Rura Penthe is also the name of the prison planet in Star Trek VI: The Undiscovered Country (1991).

One of at least three films to feature J. S. Bach's Toccata & Fugue in D minor, the others being Fantasia (1940) and Rollerball (1975).

Peter Lorre has appeared in two science fiction submarine movies , this one and Voyage to the Bottom of the Sea (1961).

In this film, the power source for the Nautilus is clearly implied as nuclear power. This is intimated by, among other things, the nuclear explosion of Nemo's island at the end of the film. In the original Jules Verne novel, however, Nemo explains to the professor a system which most resembles a fuel-cell battery originally powered by coal burning. Disney's decision on this matter was clearly influenced by the discovery of nuclear energy (i.e. the atomic bomb) only 10 years before this film. Meanwhile, in the 21st century, it is predicted that cars will run on fuel cell batteries and the original power source will be coal-fired power plants, which is ironically a return to Verne's ideas from 150 years ago.

Although Nemo dies in this movie, his fate was left unknown in the original Jules Verne novel, and he reappeared in the sequel, Mysterious Island.