A 1971 Made-for-TV Movie created by Irwin Allen as a Poorly Disguised Pilot for a new TV series. City Beneath the Sea followed retired Admiral Michael Matthews as he is brought back into service to return to his job as administrator of Pacifica, the titular city, as it deals with a looming crisis brought about by the transfer of Fort Knox's gold reserves to Pacifica.
This series provides examples of the following tropes:
- Apparently Human Merfolk: Dr. Raymond Aguila is adapted for amphibious life by having gills surgically implanted in his neck.
- Artistic License Nuclear Physics: All the gold being delivered to the city becomes really handy when the city is also ordered to store the United State's supply of an incredibly active radioisotope. Never mind that lead, or even all the water around the city, would be a cheaper and more effective method of shielding the isotope, and the radiation would also make the gold absolutely worthless as a economic commodity.
- Casting Gag: Richard Basehart appears as the President. Previous he starred in Allen's other underwater series Voyage to the Bottom of the Sea.
- Colony Drop: Midway through the movie, in the middle of dealing with other crises, Matthews finds out that an asteroid is headed for the Earth and is going drop directly onto the city.
- President Iron: Basehart's President gives Matthews a lot of grief over the course of the film, first demanding he take over operations of Pacifica, and then forcing him to accept emergency shipments of a highly unstable radioactive isotope.
- Stock Footage: Footage of the Flying Sub from Voyage to the Bottom of the Sea is used in beginning.