X: The Unknown
“It rises from 2000 miles below the earth to melt everything in its path!”
Synopsis
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 the fissure.
Trailers, Teasers & Extra Featurettes
Official promotional previews, behind-the-scenes footage, and exclusive clips.
4K Restoration | Official TrailerOfficial
Type: Trailer • Published 2026-05-01
Top Cast
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Dean Jagger
Dr. Adam Royston
Leo McKern
Inspector McGill
William Lucas
Peter Elliott
Edward Chapman
John Elliott
John Harvey
Maj. Cartwright
Michael Ripper
Sgt. Harry Grimsdyke
Anthony Newley
LCpl. 'Spider' Webb
Ian MacNaughton
Pvt. Haggis
Peter Hammond
Lt. Bannerman
Kenneth Cope
Pvt. Lansing
Michael Brooke
Willie Harding
Frazer Hines
Ian Osborn
Neil Wilson
Russell
Stella Kimball
Willie's Nurse
Jameson Clark
Jack Harding
Jane Aird
Vi Harding
Neil Hallett
Harry, the amorous intern
Marianne Brauns
Zena, the amorous nurse
Release History & Theatrical Window
May 1, 1957
Wide Cinema Exhibition
June 9, 2022
Physical Home Media
Key Information & Fast Facts
- Director
- Leslie Norman
- Screenplay & Story
- Jimmy Sangster
- Original Score
- James Bernard
- Original Title
- X: The Unknown
- Country of Origin
- United Kingdom
- Spoken Languages
- English
- Runtime
- 1h 21m
- Production Studios
- Hammer Film Productions
Creative Leadership & Key Crew
Leslie Norman
Jimmy Sangster
James Bernard
Gerald Gibbs
James Needs
Anthony Hinds, Michael Carreras
Department Leadership Roster
Jimmy Sangster
Screenplay
Leslie Norman
Director
James Bernard
Original Music Composer
James Needs
Editor
Gerald Gibbs
Director of Photography
Anthony Hinds
Producer
Age Classification & Content Advisories
Official viewer rating standards and content warnings across international classification boards.
International Certification Matrix
FSK 16 — Restricted to viewers aged 16 and older.
Parental Guidance — Unlikely to upset children 8 and older.
Production Stills & Gallery
Official cinematic photography and background stills for X: The Unknown.
Featured In Curated Collections
Editorial lists, community rankings, and cinematic collections featuring X: The Unknown.
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Frequently Asked Questions About X: The Unknown
Quick factual answers about cast, synopsis, director, box office, and release information.
What is X: The Unknown about?
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 the fissure.
Who directed X: The Unknown?
X: The Unknown was directed by Leslie Norman.
Who stars in X: The Unknown?
The principal cast of X: The Unknown includes Dean Jagger, Leo McKern, William Lucas, Edward Chapman, John Harvey.
When was X: The Unknown released and how long is it?
X: The Unknown was released in 1956 with a total runtime of 1h 21m.
Who composed the musical score for X: The Unknown?
The original motion picture soundtrack for X: The Unknown was composed by James Bernard.
What is the age rating and content advisory for X: The Unknown?
X: The Unknown holds official age classifications: DE: 16 (FSK 16 — Restricted to viewers aged 16 and older.); GB: PG (Parental Guidance — Unlikely to upset children 8 and older.).