- Country: USA
- Genres: Horror, Sci-Fi
- Release: 1957-08-12
- Director: Charles Marquis Warren
- Writers: Kenneth Higgins
- Language: English
- Stars: John Howard , Mala Powers , Paul Richards , May Wynn , Gerald Milton , Duane Grey , Richard Gilden , Martin Garralaga , Patrick O’Moore , William Hamel
- Runtime: 77 min
- Awards: N/A
- AKA: Terror desconocido (Mexico) , Beyond Terror (United States of America) , Okänd terror (Sweden) , To mystirio tis mavris frikis (Greece) , The Unknown Terror , The Unknown Terror (United Kingdom) , Terror desconocido (Argentina) , Terror desconocido (Spain) , The Unknown Terror (United States of America) , Caverna do Terror (Brazil)
- Plot: The mysterious disappearance of Jim Wheatley (Charles Gray), while exploring a cave near a Mexican village, brings his sister, Gina (Mala Powers), and her husband, Dan Matthews (John Howard), to the territory to search for him. Embittered, crippled Pete Morgan (Paul Richards), insists on going along and reminds Dan that his condition is Dan's fault since it happened in an accident in which Pete saved Dan's life. Plus, Gina was Pete's sweetheart before the accident. Did we mention embittered? The party hears about an old Indian legend concerning the Cave of the Dead where human sacrifices were made to the Gods. Dr. Ramsey (Gerald Milton), married to a native girl, Concha (May Wynn), claims no knowledge of the cave, but he is here because the climate is ideal for rapid fungus growth for his work on cultivating fungus for antibiotics. You don't have to be from France to know that if the climate is good for fungus growth, a cave is even better but it takes Dan and Pete a while to get around to that.
- IMDB:tt0051137
The Unknown Terror Cast · · · ALL
Charles Marquis Warren
Director
John Howard
Dan Matthews
Mala Powers
Gina Matthews
Paul Richards
Peter Morgan
May Wynn
Concha Ramsey
Gerald Milton
Dr. Ramsey
Duane Grey
Lino
Richard Gilden
Raoul Koom
Martin Garralaga
Lead Villager
Patrick O’Moore
Dr. Willoughby
William Hamel
Mr. Trainor
Sir Lancelot
Sir Lancelot
Charles Cirillo
Native (uncredited)
Foster Hood
Native (uncredited)