During the tense period of the Cold War, the U.S. government sought to deploy a potent new weapon against the Soviet Union: mind-reading.

In a highly classified project conducted first in a California research lab in the 1970s, and later at an Army base in Maryland, the CIA, Army and Defense Intelligence Agency recruited men and women claiming to have powers of extrasensory perception (ESP) to help uncover military and domestic intelligence secrets.

In 2017, the CIA declassified some 12 million pages of records revealing previously unknown details about the program, which would eventually become known as Project Star Gate. By the time the program was shut down in 1995, psychics known as “remote viewers” had taken part in a wide array of operations, from locating hostages kidnapped by Islamic terrorist groups to tracing the paths of fugitive criminals within the United States.

The roots of Project Star Gate go back to 1972, when a classified report made waves within the U.S. military and intelligence communities by claiming that the Soviet Union was pouring money into research involving ESP and psychokinesis—the ability to move objects with the mind—for espionage purposes. In response, the CIA began funding its own top-secret research, headquartered at the Stanford Research Institute in Menlo Park, California.

Read more: The CIA's Appalling Human Experiments With Mind Control

Ex-Israeli paratrooper, Uri Geller, became famous for his ability to bend metal cutlery with his mind. A. Schorr/ullstein bild/Getty Images

Psychic Uri Geller led ESP investigations.

Late that year, the research team at SRI invited Uri Geller, an ex-Israeli paratrooper who had become internationally famous for his psychic powers, to Menlo Park for testing. Though Geller was best known for his alleged ability to bend metal cutlery with his mind, the CIA was much more interested in another of his professed skills: the ability to read other people’s minds, and even control their minds with his own.

As Annie Jacobsen writes in her book Phenomena: The Secret History of the U.S. Government’s Investigations into Extrasensory Perception and Psychokinesis, the declassified documents show that CIA analysts wanted to probe Geller’s abilities in the area of “mind projection” and its possible use for national security purposes.

According to Jacobsen, Geller played a key role in setting into motion the U.S. government’s investigation into ESP and psychokinesis. In the winter of 1975, she writes, Geller even took part in a series of classified psychokinesis tests at a lab in Livermore, California, where scientists were developing advanced nuclear warheads, laser systems and other emerging weapons technologies.

In one experiment for the CIA, Geller was isolated in a room and told a picture had been drawn. He then drew a picture of a square with diagonals drawn. Central Intelligence Agency

The CIA shut down its work with ESP in the late 1970s, and the program moved to the U.S. Army’s Fort Meade in Maryland, where it was funded by the Defense Intelligence Agency. Over the better part of the next two decades, Congress continued to approve funds for the remote viewing program.

“It seems to me a hell of a cheap radar system,” Rep. Charlie Rose of North Carolina told fellow members of the House Select Committee on Intelligence during a meeting about psychic research in 1979. “And if the Russians have it and we don’t, we’re in serious trouble.”

Psychics helped with top-secret programs.

Army veteran Joseph McMoneagle stood out among the remote viewers who worked with the government’s top-secret program. As he later told the Washington Post, McMoneagle was involved in some 450 missions between 1978 to 1984, including helping the Army locate hostages in Iran and pointing CIA agents to the shortwave radio concealed in the pocket calculator of a suspected KGB agent captured in South Africa.

Another remote viewer, Angela Dellafiora Ford, was asked in 1989 to help track down a former customs agent who had gone on the run, she recounted recently on the CBS News program 48 Hours. She was able to pinpoint the man’s location as “Lowell, Wyoming,” even as U.S. Customs was apprehending him 100 miles west of a Wyoming town called Lovell.

Publicly, the Pentagon continued to deny it was spending money on any kind of psychic research, even as reports leaked out in the 1980s of the details of the government’s experiments. Finally, in 1995, the CIA released a report conducted by the independent American Institutes for Research, which acknowledged the U.S. government’s long-rumored work with remote viewing for military and intelligence purposes.

The report also declared Star Gate as a failure, arguing that “it remains unclear whether the existence of a paranormal phenomenon, remote viewing, has been demonstrated.” Though the analysts acknowledged that some trials had been successful and that “something beyond odd statistical hiccups is taking place,” they concluded that any information remote viewing had provided had been too “vague and ambiguous” and did not produce “actionable intelligence.”

'Spidey sense' was investigated among Marines.

The shutdown of the program that year did not mark the end of the government’s interest in psychic phenomena. In 2014, Jacobsen writes, the Office of Naval Research launched a four-year program (costing some $3.85 million) to explore the use of premonition or intuition—what is popularly known as a “sixth sense” or even a “Spidey sense,” in honor of the web-throwing superhero—among sailors and Marines. And Dr. Edwin May, the former Star Gate research head, has continued to argue on behalf of ESP as a legitimate tool for military and domestic intelligence long after the program was shut down. In 2015, May told Newsweek that his most recent ESP study, funded by the non-profit Bial Foundation, “is probably the best experiment in the history of the field.”

Whatever its use for espionage purposes, belief in the powers of ESP has a long-running history of support among ordinary Americans: According to a 2005 Gallup poll, 73 percent of Americans at the time believed in some kind of paranormal phenomena, with 41 percent of those polled saying they believe in ESP specifically.