Roger Corman had planned to do a movie titled "Captain Nemo and the Floating City" based on two Jules Verne stories, "20,000 Leagues Under the Sea" and "The Floating City." The project eventually was scrubbed. But after reading about Jacques-Yves Cousteau's experiments in underwater habitats, MGM producer Steven Pallos picked up the project, moving the city under water. The film drew heavily on the supposed charm of the Victorian era, following agreement between director and scriptwriters to produce a popular escapist atmosphere, more the essence of Michael Todd's Around the World in Eighty Days (1972) than of Disney's 20,000 Leagues Under the Sea (1954).
Although centered on a character created by Jules Verne (Captain Nemo from both Captain Nemo and the Underwater City (1969) and Mysterious Island) the plot of this film was not from an existent Verne novel, but was concocted by the screenwriters of this movie.
This film was made in the UK on a shoestring budget, then acquired by M-G-M for U.S. distribution as part of their Family Matinee collection.
Luciana Paluzzi, who plays "Mala," is best remembered as a redheaded SPECTRE temptress in the fourth Sean Connery James Bond movie Thunderball (1965).
Produced on a budget of $1.5 million, which is the equivalent of $12.2 million in 2022.