X: The Unknown (1956) is a Horror, Science Fiction, Mystery film that follows 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. X: The Unknown is not currently listed with streaming providers in your selected region, but availability can change over time. It has a user rating of 6.1 out of 10 from 74 votes. Fans of horror movies may also want to explore similar titles below.