Unknown World was made by two Hollywood special effects men, Jack Rabin and Irving Block, who are two of the film’s three producers. It was directed by Terry O. Morse, who shot the American scene in Godzilla, and written by Millard Kaufman, who also wrote Bad Day at Black Rock and The Klansman.

Victor Kilian, who plays Dr. Jeremiah Morley, lost an eye in a fight scene with John Wayne and was blacklisted for decades due to his political views, which is why he is uncredited in this. He’s invented a big tank that can drill into the center of the world, the Cyclotram, and has taken a crew of scientists through Carlsbad Caverns, Bronson Caves, Nichols Canyon and finally Pismo Beach to find a place where the human race can survive a nuclear war. Sadly, that unknown world makes everyone sterile.

Let me tell you, people were obsessed by the center of the Earth in 1951.

Have you ever heard of the Shavers?

Richard Shaver first encountered these creatures from Lemuria when the tools at his factory job started playing other peoples’ thoughts into his brain. He could also hear the Shavers torturing people underground. Now, you may say that he was mentally ill, but he also was writing to the pulp magazine Amazing Stories. He claimed to have discovered an ancient language he called Mantong. Editor Ray Palmer (the namesake of DC Comics’ Silver Age version of The Atom) thought that Shaver was onto something. He helped him write A Warning to Future Man,” where Shaver discussed cities within the Earth, populated by the good Teros and the evil Deros. This was turned into “I Remember Lemuria!” which appeared in the March 1945 issue of Amazing Stories. That issue instantly sold out and then something really odd began: thousands of letters began appearing saying that they’d had the same experiences as Shaver.

Amazing Stories‘ readership either loved or hated the Shaver stories. According to Wikipedia, “Palmer would later claim the magazine was pressured by sinister outside forces to make the change: science fiction fans would credit their boycott and letter-writing campaigns for the change. The magazine’s owners said later that the Shaver Mystery had simply run its course and sales were decreasing.”

That didn’t end the Shaver stories. Palmer credits these tales with the public fascination with UFOs. John Keel’s 1983 Fortean Times piece “The Man Who Invented Flying Saucers” claims that “a considerable number of people — millions — were exposed to the flying saucer concept before the national news media were even aware of it. Anyone who glanced at the magazines on a newsstand and caught a glimpse of the saucer-emblazoned Amazing Stories cover had the image implanted in his subconscious.” Indeed, Palmer was quick to defend the Shaver stories and claim that “flying saucers” were their validation.

Palmer’s newsletter after The Shavers were forced out of Amazing Stories? The Hidden World.

Don’t have the box set? You can watch this on Tubi.