Vulcania is the secret island port of origin for the Nautilus and Captain Nemo's one land-based home.
20,000 Leagues Under the Sea
Vulcania is not mentioned in the original Jules Verne novel. Not much is stated about the fictional island in the 1954 film 20,000 Leagues Under the Sea. It is briefly mentioned by Nemo after he shows Pierre Aronnax the penal colony of Rura Penthe. A later scene has Ned Land locate the island on a nautical chart. The island is only very briefly visited near the end of the film, during which time only a few brief glimpses are seen. Several docks are visible, suggesting that the lagoon contains a harbor for the Nautilus and possibly other boats. Several much larger buildings are visible, but their purpose is unknown.