Captain Nemo and the Underwater City (1969)

Captain Nemo (Robert Ryan) rescues six people from a floundering ship from certain death. Senator Fraser (Chuck Conners) the scientist Professor Lomax (Allan Cuthbertson), and the other four passengers are taken to the underwater city of Templemer. The underwater domed city is a self sufficient refuge far removed from the bellicose world outside. Oxygen, building materials, food and gold are all produced on the ocean floor. The six rescued travelers become trapped in Templemer when Nemo refuses their requests to leave. Fearing news of the underwater paradise will bring unwanted attention, the travelers are trapped. Each one wishes to leave for their own selfish reasons as they conspire to escape the domed fortress in this feature inspired by the Jules Verne character.