 It remained unreleased for three years until it was put on the bottom of a double feature with another of Jerry Warren's films, "Teenage Zombies", on April 16, 1960.Warren had a monster suit built to use in the film, but "it ended up looking too bad even for Warren", so the suit was scrapped.The ad line retained the mention of the monster however, stating "A Nightmare of Terror in the Center of the Earth with Forgotten Men, Monsters, Earthquakes and Boiling Volcanos!"