Where to watch X: The Unknown (1956) tonight
X: The Unknown (1956) runs 1 h 21 min and averages 6.1 from 78 TMDB members. Army radiation experiments awaken a subterranean monster from a fissure that feeds on energy and proceeds to terrorise a remote Scottish village. An American research scientist at a nearby nuclear plant joins with a British investigator to discover why the victims were radioactively burned and why, shortly thereafter, a series of radiation-related incidents are occurring in an ever-growing straight line away from…
- Runtime
- 1 h 21 min — ends 9:21 pm if you start at 8:00 pm
- Rated
- no US certification listed
- Genres
- Horror, Science Fiction, Mystery
- Released
- September 21, 1956
- TMDB rating
- 6.1 / 10 from 78 votes
- Director
- Leslie Norman
- Starring
- Dean Jagger, Leo McKern, William Lucas, Edward Chapman
- Language
- English
Where to watch it tonight
Availability loads live for your country. See where X: The Unknown streams (JustWatch via TMDB) →
Streaming availability by JustWatch. In the US, as of 2026-11-05: Mometu (free with ads).
Questions people ask
- How long is X: The Unknown?
- X: The Unknown is 1 h 21 min long (81 minutes). If you start it at 8:00 pm it ends at 9:21 pm; add about 20 minutes if you watch trailers first.
- What is X: The Unknown rated?
- TMDB lists no US age certification for X: The Unknown.
- Is X: The Unknown a good movie to watch with a group?
- Yes — a crowd movie. Horror and Science Fiction hold a room: people can talk, laugh or scream over it and still follow what is going on.
- Where can I stream X: The Unknown?
- In the US, as of 2026-11-05: Mometu (free with ads). Availability changes often; this page loads the live list for your country (streaming availability by JustWatch).
Lists it could be on
- Horror movies under 90 minutes
- Sci-fi movies under 2 hours
- Mystery movies under 2 hours
- The most-rated movies on TMDB
If you like X: The Unknown
- Quatermass 2 (1957)
- The Giant Behemoth (1959)
- Them! (1954)
- Underwater (2020)
- The Blob (1958)
- The Return of Doctor X (1939)
- Island of Terror (1966)
- The Car (1977)
X: The Unknown on TMDB · This product uses the TMDB API but is not endorsed or certified by TMDB.
Lights Down is a free tool: tell it your streaming services and how long you have, and it ranks what you can stream tonight, with a this-or-that, a roll, a bracket and a wheel. Movie data from TMDB; streaming availability by JustWatch. Page updated 2026-11-05. 
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