Press interviewing victorious Fidel Castro en route to rebel victory celebration in Havana, Cuba, in 1959.

Famous declassified government secrets

Written by:
June 17, 2019
Lee Lockwood // Getty Images

Famous declassified government secrets

Hidden and secretive government agencies have long captured the public's imagination. The TV series "The X-Files" imagines FBI agents whose job is to understand paranormal phenomena, though they uncover a government conspiracy to keep extraterrestrial life a secret in the process. In "Men In Black," agents work alongside aliens to protect the Earth from otherworldly threats. Closer to home, conspiracy theories about hidden life on Earth persist. As recently as June 2019, the FBI released a trove of files related to Bigfoot, further stoking speculation on whether the mystical Sasquatch could be successfully hiding from humanity. 

There's a common idea that unites ghost-hunters and Bigfoot-truthers alike: The government must be hiding something. Somewhere in its vast archives, they reason, there must be evidence of events beyond explanation, or at least an honest historical record of some of the most shadowy points in America's history. Many would jump at the chance to review the unredacted files on the J.F.K. assassination, learn about the inner negotiations of the Cuban Missile Crisis, or find out if aliens really do exist. 

Sometimes, the U.S. government declassifies files that it decides are safe to be released to the public. While this seems like a transparent act, oftentimes it does little more than tease conspiracy theorists who may never live to see the entire truth unearthed. However, there's some fascinating information in the files that have been released: Did you know the U.S. government once considered building a moon base? And contemplated training cats to be soldiers?

Stacker went into the files and pulled out the top 30 juiciest, most interesting government secrets. All of them have been declassified, meaning the governments in question have released documents confirming the truth. Everything we've learned is only a small subset of the secrets the government holds. What other information is out there? Could the truth be stranger than fiction? We may not have all the answers, but read on to find out what we do know about the government's most closely held secrets. 

You may also like: States with the most UFO sightings

Operation Paperclip

On the heels of World War II and as the Cold War began in earnest, both the United States and the Soviet Union recruited ex-Nazi scientists, like Wernher von Braun who had relied on slave labor from concentration camps, to design Germany's V-2 rockets. The United States alone secured 88 ex-Nazi scientists during what was termed "Operation Paperclip" in order to learn more about Nazi Germany's powerful weapons and technology. It's partly because of this secret operation that we now know about Hitler's extensive chemical warfare program.

Area 51

A classic birthplace of conspiracies about fallen alien ships and little green men, Area 51 is shrouded in mystery. According to ex-government sources, this mysterious area of Nevada is mostly a test site for experimental military technology, like the super-fast SR-71 Blackbird airplane, and not a secret extraterrestrial testing facility. Which is still cool, given the plane can reach three times the speed of sound—even if aliens aren't involved. A declassified CIA report in 2013 mentioned Area 51 by name, and even marked it on a map.

Bigfoot in Oregon?

Bigfoot, or Sasquatch, is a long-rumored bipedal mammal that dwells in the wilderness of the Pacific Northwest. More simply, it's allegedly a hairy ape that walks around leaving behind footprints for people to find and appearing in blurry photographs. The FBI in 1976 officially investigated unidentifiable hairs from The Dalles, Oregon, that people believed may have belonged to Bigfoot. The investigation—declassified in 2019—proved inconclusive, but that doesn't mean Bigfoot isn't still out there.

Project MK-ULTRA

The designation of "Ultra" was given to the most secret projects and documents used by the government during World War II. In 1953, during the early years of the cold war, Project MK-ULTRA was sanctioned as an ultra-secret project to develop drugs and other practices for mind control of interrogated subjects. Many of its experiments happened on unwitting participants and were clearly illegal, leading to international controversy. This now-declassified government project has been tied to many conspiracy theories, but documents definitively point to experiments around animal mind control and hallucinogens.

Attempts to assassinate Fidel Castro

During the Cold War, the U.S. intervened in many foreign countries to prevent the spread of Communism. Government bureaucrats worried about the domino effect, whereby if one country fell to Communism, all the other countries in the area would also be likely to revolt. Fidel Castro, who led Cuba into a Communist revolution despite having relatively few resources and people, was no ally to the CIA. But declassified documents reveal that the CIA even went so far as to negotiate with mobsters to put out a hit on the dictator, hoping to install a more U.S.-friendly leader of the nearby island. 

Julia Child's wartime activities

Originally rejected from the military for being too tall (she was 6'2"), Julia McWilliams joined the Office of Strategic Services in 1942 and quickly worked her way up the ranks. Known today for her wit, television shows, and her introduction of French cuisine to Americans, Julia Child's work in espionage was revealed after her death in declassified documents. Among her accomplishments? Helping to formulate an effective shark repellant for divers.

Investigating John Lennon

Thanks to the efforts of journalist Jon Weiner, records emerged around the FBI's extensive investigation of John Lennon in the early 1970s. The FBI suspected Lennon would disrupt proceedings in the 1972 presidential election, where Nixon hoped to be reelected, with a planned tour complete with voter registration efforts and antiwar protests. To help stop him, the Immigration and Nationalization Service, which would later be absorbed into the Department of Homeland Security, began deportation proceedings against Lennon. It appears that their preemptive efforts worked; Lennon never did the tour, and Nixon was reelected.

Secret spy tricks

In today's era of end-to-end encryption, secure digital back-channels, and disappearing text messages, it's easy to forget the CIA's spy work that went far beyond wiretapping phone lines and bugging meeting places of persons of interest. The agency had apparently figured out a way to open sealed envelopes without detection, according to declassified documents about procedures for examining mail without leaving a trace. The CIA also detailed formulas for invisible ink.

Project Iceworm

Desperate to gain an edge over the Soviets in any way possible, the United States built a state-of-the-art, underground, nuclear-powered research facility called Camp Century in the remote tundra of Greenland. The U.S. toured this facility to the press; what they didn't mention was Project Iceworm, the plan to build 2,500 miles of tunnels underneath the ice sheet that would be used to shuttle nuclear missiles back and forth, evading Soviet attempts to destroy them. Over time, the project was canceled and Camp Century itself was abandoned; now, with Greenland's ice melting due to climate change, scientists have raised concerns about the radioactive material that once powered Camp Century eventually returning to the surface.

The truth about Argentina's dictatorship

Argentina's military dictatorship of the 1970s was marked by distrust, disappearances, and a murky relationship with the United States. But declassified CIA documents revealed that the regime was just as deadly as suspected——even employing assassination squads to eliminate enemies, many of whom disappeared without a trace. Now we know they were murdered by the Argentinian state and its assassins, who clocked in at 9:30 a.m. and even submitted expense reports. 

The My Lai Massacre

In one of the darkest moments of American military history, U.S. military forces opened fire on the citizens of My Lai, a small hamlet in Vietnam, killing hundreds of civilians (mostly women, children, and old men). The savagery included sexual assault and the eventual destruction of the village. More than a year passed before Cleveland's Plain Dealer newspaper published Ron Haeberle's photos of the destruction, revealing the massacre to the world. A declassified government report details the extent of the violence Americans wrought against the Vietnamese and the government's process in inquiring about the events that took place. 

A Bomb meant for New Mexico ended up in...Mexico

The United States in 1970 launched a test rocket from Utah bound for New Mexico, according to declassified reports. The rocket landed in the Mapimi desert in Mexico by accident. Cleanup was long and extensive, partially due to the fact that the missile contained cobalt 57, a radioactive isotope that turns ordinary explosives into "salted bombs"—thankfully Mexico recognized it as a mistake, and was willing to assist search efforts for the bomb. 

The USA "borrowed" the Lunik

The Soviet Union in 1967 offered tours of its Lunik and Sputnik models, both advanced satellites integral to the Soviet space program. Unbeknownst to the Soviets, United States operatives stole the Lunik to gather information on its inner workings and returned it before anyone noticed. The operatives later wrote about the unofficial loaner in an internal CIA journal to debrief—or maybe brag to—the rest of the agency.

Responsibility for the USS Liberty

While caught up in the Six-Day War, Israel in 1967 attacked the warship USS Liberty, exacerbating tensions between the U.S.—neutral in the conflict—and other Middle East states. But declassified documents revealed that communication errors from Israel and the U.S. were likely more to blame than a desire for war, though some former soldiers maintain that the attack was deliberate.

The Bikini Atoll tests

The U.S. military tested 23 nuclear explosive devices in the tiny island system of Bikini Atoll between 1946 (the year after the bombings of Nagasaki and Hiroshima) and 1958, after relocating the islands' original inhabitants elsewhere. Expanded materials about the Bikini Atoll nuclear tests were officially declassified in 2016. Among them were details about the extreme radiation contamination that took place, as well as video footage of the infamous mushroom clouds.

The Cold War books

The CIA had a hand in many different aspects of the Cold War crisis, including the distribution of the then-banned book "Dr. Zhivago" throughout the Soviet Union. Penned by revered Russian writer Boris Pasternak, the classic novel was judged to have "great propaganda value" in its time and even won Pasternak a Nobel Prize in Literature, further embarrassing the Soviet government that had refused to publish it. More than 10 million books and magazines were distributed by the CIA behind the Iron Curtain during the Cold War. 

Plans for a moon base

Permanent human settlements on other planetary bodies have long been a staple of science fiction, precipitated by curiosity, a desire for colonization, or even the destruction of the Earth itself. Here, reality almost mirrored the fiction: Declassified plans reveal that America studied the possibility of a moon base in 1960. The study included details such as what equipment was needed for setup and which contractors would support the project, Boeing among them.

Trained cat soldiers

Documents declassified in 1983 reveal that the U.S. government tested the idea of training cats to be spies, implanting recording equipment in their bodies and letting them loose near the Kremlin or Soviet embassy. Millions of invested dollars later, the program was shut down. Although the cats could travel short distances successfully, the training was insufficient for the CIA's complicated eavesdropping needs. 

The fake Titanic search

The expedition that uncovered the sunken remains of the RMS Titanic was sponsored by the U.S. Navy. As declassified documents reveal, the Navy was actually looking for sunken 1960s ships USS Scorpion and the USS Thresher and their nuclear payloads. The underwater "unsinkable ship" was just cover story—and bonus discovery. 

America knew about Sputnik

Americans were shocked to learn that the Soviet Union had launched a satellite into space in 1957. This achievement marked the beginning of the Space Race and the first of many victories for the Soviet Union, including sending Yuri Gagarin to be the first human in space. Though the public was unaware of the Soviet Union's otherworldly ambitions, the American government and its intelligence community were already in the know about Sputnik.

The Tiananmen Square death count

Declassified documents from Great Britain show that the 1989 Tiananmen Square massacre's death toll was closer to 10,000 civilians, not the oft-cited number of 3,000, and much higher than the Chinese government's own tally that puts the mark between 200 and 300. The secret diplomatic cable was written slightly more than 24 hours after the event took place.

The U.S. relationship with Khomeini

Declassified records have revealed that Ayatollah Ruhollah Khomeini, a cleric who would later emerge as a driving force in Islamic fundamentalism, was much closer to the American government than previously thought. Khomeini had sought to negotiate with the Kennedy and Carter administrations in order to ease his takeover of Iran, despite his public anti-American rhetoric, going as far as to call America "the Great Satan."

Churchill's plan for Hitler

Winston Churchill was not interested in deciding the fates of Adolf Hitler and other Nazi leaders in a court of law. Referring to Hitler as the "mainspring of evil," declassified documents reveal that Churchill argued for the execution of Nazi leaders in opposition to Allied plans for war crimes trials. Churchill must have relented, as the remaining Nazi leaders were subjected to the Nuremberg Trials starting in 1945. Hitler and Goebbels, among others, killed himself shortly before the end of the war to avoid capture. 

Code name: Corona

The CIA's Corona project used satellites to take photographs of the Middle East and China between 1959 and 1972. Originally used for military intelligence, the pictures have since been declassified. Now, they've proven to be of great use to archeologists studying the region; the scientists can track changes over time to historically important sites.

Alaska's invasion plan

Declassified documents have revealed that the U.S. government, out of fear of an invasion of Alaska by Soviet paratroopers, trained U.S. citizens in Alaska to become spies. Newly minted spies, many of whom previously worked jobs as fishermen and trappers, kept the government informed of Soviet movements. Project Washtub, as it was known, was active between 1951 and 1959, though the Soviets never attempted to capture Russia back after its purchase by the U.S. in 1867. 

Our hero Stanislav Petrov

In 1983, a Soviet Union soldier named Stanislav Petrov opted not to fire nuclear missiles when it appeared that the United States had launched five missiles at his country. He had judged correctly that it was a false alarm, thereby averting a third and possibly final nuclear World War. The world learned of his clear-headed judgment in declassified records released in 1998.

The Dunblane Massacre Troubles

The Dunblane Massacre was a tragic school shooting in 1996 that killed 16 children and one teacher at a primary school in Scotland. Declassified documents confirm the shooter had in the past been reprimanded for inappropriate behavior around children, though criminal charges were never brought. There have also been allegations of media management to hide the lack of government action on these complaints.

Nixon's treason?

When the telephone calls of President Lyndon B. Johnson were declassified, it was revealed that then-candidate Richard Nixon negotiated with South Vietnam behind the president's back. South Vietnam withdrew from the Paris Peace talks after being told that Nixon would get them a better deal once elected. Nixon was concerned that an early end to the war would derail his election campaign, since the Vietnam war was a pressing campaign issue. Nixon ended up winning the election by less than 1% of the popular vote. 

The legacy of Oleg Penkovsky

Col. Oleg Penkovsky was a Russian double agent who regularly supplied information to MI6 and the CIA. Declassified documents reveal that it was his information gathering within Russia and abroad that alerted America to the presence of Soviet missiles in Cuba, thereby kickstarting the Cuban Missile Crisis. 

The missing Thule bomb

During the Cold War, the American army base in Thule, Greenland, was patrolled continuously by planes armed with nuclear missiles. After one of the planes went down, the public believed every bomb therein had been accounted for. Declassified documents revealed that one nuclear bomb was in fact never found. While that may sound scary on its own, missing nuclear bombs and nuclear scares are frighteningly common.

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