By definition, a conspiracy is an agreement between two or more people to commit a crime, fraud, or wrongful act. While little conspiracies likely occur every day, bigger conspiracies lurk underneath the surface of society. While many of them involve the illegal transfer of money or drugs, others affect the public at large in strange, frightening, and existential ways. These plots often involve governments, large organizations, and powerful bad actors. In this article, we will explore 10 conspiracy theories that were actually true.
To compile a list of conspiracy theories that were actually true, 24/7 Tempo consulted a range of entertainment, historical, and periodical publications. Next, we selected large-scale conspiracies with plenty of evidence showing their actuality. After that, we confirmed aspects of the conspiracies using sites like Encyclopedia.com and Britannica.com.
This post was updated on October 13, 2025 to clarify Seymour Hersh’s 1974 NYT reporting and the 1975 Rockefeller Commission on MKUltra; the CDC’s part in the Tuskegee Syphilis study; the 1974 National Research Act and the 1979 Belmont Report; when COINTELPRO was exposed; that JIOA ran Operation Paperclip, the number of scientists brought to the U.S., and that dossiers were sanitized; and the Black Sox scandal.
MKUltra
One of the actually true conspiracy theories is Project MKUltra. Undertaken by the Central Intelligence Agency (CIA) during the 1950s, 60s, and 70s, the program sought to find drugs and other mind-altering techniques that made people amenable to interrogation and brainwashing/mind control. Starting in 1953 and culminating in 1973, the program took place surreptitiously at various universities, hospitals, and prisons within the United States and Canada.
While MKUltra cast a wide umbrella in terms of its aims, its practices were varied, including sensory deprivation, high-dose LSD, electroshock, and taped-loop ‘psychic driving’ in some subprojects. The success of these experiments is unknown; however, many countercultural figures like Ken Kesey, Allen Ginsberg, and even gangster James “Whitey” Bulger were subjects of the program.
The program came to light through Seymour Hersh’s 1974 NYT reporting and the 1975 Rockefeller Commission. Following these, the Church Committee of the United States Congress unveiled evidence to the public. The committee had to rely mostly on sworn testimony, as the previous CIA Head Richard Helms ordered most of the MKUltra documentation destroyed in 1973. A few years later, however, thousands of documents related to the project came to light, detailing the true scope and horror of the mind-control techniques the CIA employed on unsuspecting citizens.
Tuskegee Syphilis Experiment
Another one of the actually true conspiracy theories is the Tuskegee Syphilis Experiment. Conducted between 1932 and 1972 by the United States Public Health Service (PHS), the program sought to discover what happened to people with untreated ailments like syphilis. (The Center for Disease Control (CDC) later became involved/consulted.)
While it sounds above board in theory, in practice, the government organizations lied to all of the patients involved in the program. For one, they never told the patients they had syphilis. Instead, they labeled their conditions as things like ‘bad blood.’ Furthermore, the patients (mostly black male sharecroppers from Alabama) thought they would receive free medical care while participating. Instead, they weren’t treated for anything, forced to experience the painful effects of syphilis when medicine like penicillin was already available by 1947.
A leak of the project to the press in 1972 caused the PHS to terminate the project. By then, over 128 subjects had died directly from syphilis or complications arising from the disease. The revelation of the project led to the 1974 National Research Act and the 1979 Belmont Report. The Office for Human Research Protections (OHRP) was later created until 2000. Furthermore, President Bill Clinton publicly apologized for the program, saying “What the United States government did was shameful and I am sorry.”
Bohemian Grove
Another verified conspiracy theory centers on the existence of Bohemian Grove. Founded as an extension of the Bohemian Club, a private men’s club in San Francisco, the Grove occupies a secluded forest in Sonoma County. Since its establishment in 1878, it has drawn some of the most powerful figures in American politics, business, and culture, while also inspiring decades of speculation and myth.
Over the years, Bohemian Grove’s guest list has reportedly included presidents, politicians, intelligence officials, and entertainers (from old school authors like Mark Twain to modern day actors like Clayton Rohner). Curiosity about what happens behind its closed gates is fueled by rumors of esoteric rituals such as effigy burnings and owl worship. Perhaps most notably, the Grove hosted a preliminary gathering of the Manhattan Project in 1942, which would ultimately lead to the creation of the atomic bomb.
While Bohemian Grove exists to this day (membership is by invitation only), it’s hard to say what kind of nefarious or conspiratorial activities occurred (or didn’t occur) at this campground. Though many believe The Grove is merely a private retreat for elite men engaging in summer camp rituals, a shroud of mystery still lingers over the infamous club.
Tobacco Companies Knew the Dangers of Smoking
Another one of the actually true conspiracy theories concerns the dangers of smoking and how long tobacco companies knew about the potential harm. For many decades, doctors and public health organizations tolerated smoking. In recent years, however, uncovered evidence shows that Big Tobacco has long since known the dangers of smoking.
Big Tobacco conducted numerous scientific experiments showing that cancer grew in the lungs of regular smokers. These companies had strong internal evidence of the hazards of smoking by the early 1960s (e.g., polonium-210) and misled the public. What’s more, they also knew about the presence of radioactive substances in the tobacco they produced. They did nothing about it, however, except hide said studies and keep their conclusions from the public by any means possible.
A study published in a 2011 issue of Nicotine & Tobacco Research presented evidence showing the decades-long deception and misdirection tobacco companies used to keep this knowledge from the public. Consequences resulted in the 1998 Master Settlement Agreement, which forced Big Tobacco to pay over $200 billion over 25 years. Sweeping marketing restrictions and higher taxes were also implemented.
COINTELPRO
Another conspiracy theory that’s actually true is COINTELPRO. By the year 1956, various social and political movements were beginning to form. Many of these groups, like the Black Panther Party and United Farm Workers, broadcast rhetoric that the government felt threatened national security.
In response, the FBI set about watching, infiltrating, smearing, and disrupting various political movements between 1956 and 1971. Undertaking a war of psychological attrition, the FBI planted false reports in the media, forged documents, committed perjury, intimidated witnesses, harassed, and even contributed to the deaths of those involved in activist groups they considered to be a threat.
Some of the biggest names in activism faced the wrath of COINTELPRO, including Martin Luther King, Fred Hampton, and Malcolm X. The widespread program only came to light in 1971 after an activist group broke into an FBI office and stole relevant documents. A few years later (1975-76), the Church Committee of the United States Congress investigated the claims and found that the FBI “violated specific statutory prohibitions and infringed the constitutional rights of American citizens.”
The Business Plot
Another conspiracy that’s actually true is The Business Plot. Organized by various business leaders and industry titans, the conspiracy sought to overthrow President of the United States Franklin D. Roosevelt in a coup d’état and install Major General Smedley Butler as dictator.
Evidence of the plot surfaced after Smedley Butler apparently went against his handler’s wishes and testified under oath about the plot to the Special Committee on Un-American Activities in the House of Representatives in 1934. While the committee thought the evidence true, no one faced prosecution for their alleged involvement in the plot.
The media had a field day with the revelations, with most publications ascribing Butler’s testimony as a fantastic hoax, yet there was some truth in there. The McCormack–Dickstein Committee (a forerunner to HUAC) said there was evidence of discussions about a fascist organization. While historians now believe the plot was true, and widely discussed between alleged conspirators, they differ on how advanced the plot actually was.
Operation Snow White
Unlike other entries on this list, Operation Snow White was directed against the government instead of for it. Perpetrated by the Church of Scientology in the 1970s, the conspiracy intended to purge unfavorable reports and records about the Church’s activities. It was surprisingly successful, too.
To commit the conspiracy, the Church of Scientology broke into hundreds of government agencies, consulates, and embassies using anywhere from hundreds to thousands of agents. These agents trespassed at government institutions, created wiretaps, and stole government documents in one of the largest infiltrations in United States Government history.
There are even rumors that the Church of Scientology received its tax-exempt status after breaking into the Internal Revenue Service and holding files on individual tax agents for blackmail. While that remains unproven, eleven elite members of the church, including the founder’s wife Mary Sue Hubbard were arrested and later pled guilty to crimes like burglary of government offices, theft of documents and government property, and obstruction of justice.
Operation Paperclip
Another actually true conspiracy theory is Operation Paperclip. As World War II wound down in Europe but still raged in the Pacific, the U.S. government realized the wealth of scientific information and innovation that lay in the hands of Nazi doctors and scientists.
Paperclip was run by the Joint Intelligence Objectives Agency (JIOA) with Army/OSS support. The program found and recruited over 1,600 German scientists and their families and brought them to the United States. Upon entry to the states, dossiers were sanitized and the scientists worked on rocket programs, aviation tests, and chemical or biological warfare experiments.
As for the success of the project, many of the scientists went on to contribute greatly to America’s scientific knowledge, like famous rocket scientist Wernher Von Braun. Most were not prosecuted in the U.S., though a few later faced denaturalization/investigation (Arthur Rudolph left under pressure). The ethical implications of Operation Paperclip remain dubious.
Black Sox Scandal
Another actually true conspiracy theory takes place in the arena of American sports. Known as the Black Sox Scandal, the conspiracy involved eight members of the Chicago White Sox baseball team. They were accused of purposely losing the 1919 World Series against the Cincinnati Reds for money given to them by an organized crime gambling syndicate.
Purportedly masterminded by underworld figure Arnold Rothstein, the Black Sox Scandal sent widespread ripples through professional baseball and the greater sports arena at the time. While the eight baseball players accused of game-fixing received acquittals in a public trial, they were permanently banned from playing professional baseball.
In response to the conspiracy, numerous changes occurred to the structure of professional baseball. For one, it promptly dissolved the National Baseball Commission. Furthermore, former Judge Kenesaw Mountain Landis was appointed as the Commissioner of Baseball, effectively giving him total power over the sport.
Bayer Medicine Helped Spread AIDS
Another conspiracy theory that is actually true involves the effects of medication sold by the Bayer Pharmaceutical Company. In the 1980s, the company’s Cutter Biological unit broke federal law when recruiting gay men, intravenous drug users, and prisoners as donors for its blood-clotting medications called Factor VIII and IX.
Designed for hemophiliacs, the medicines purported to promote clotting in affected people. The problem was, however, that much of the Factor drugs circulated by Bayer contained HIV-positive blood. Though the company did its best to keep this a secret, when evidence came to light, they were forced to pay high compensation figures to affected people.
In the end, Bayer paid out tens of millions of dollars to affected hemophiliac patients who took the Factor VIII and IX drugs in the mid-1980s. As for Bayer’s moral culpability, however, the company remains unrepentant. During the outcry, the company continued to insist it always acted responsibly and ethically.
The image featured at the top of this post is ©"International", 228 William St, NY, Public domain, via Wikimedia Commons.