Unknown World

Unknown World aka Night Without Stars is a 1951 independently made, blackandwhite science fiction adventure film released by Lippert Pictures. The film was produced by Irving A. Block, Jack Rabin, and Robert L. Lippert, was directed by Terry O. Morse, and stars Bruce Kellogg, Marilyn Nash, Jim Bannon and Otto Waldis.

Dr. Jeremiah Morley Victor Kilian is concerned about an imminent nuclear war. He organizes an expedition of scientists and has them use an atomicpowered machine, the Cyclotram, capable of drilling through earth and stone, to find an underground environment where humanity could escape the coming holocaust.The expedition Jim Bannon, Marilyn Nash, Otto Waldis, Tom Handley and Dick Cogan begins after government funding has fallen through and they are bailed out at the last minute by private funding from a newspaper heir Bruce Kellogg, who insists on going with them as a lark. Romantic rivalry develops between Bannon and Kellogg for Nash, and two lives are lost to the perils of the expedition. ........

Source: Wikipedia