This is a list of important conspiracy theories. Many of these theories involve claims about secret government plans or complicated murder plots. These theories usually disagree with widely accepted opinions and cannot be proven using historical or scientific methods. They should not be confused with research about real conspiracies, such as Germany's false reasons for invading Poland during World War II.
Sometimes, conspiracy theories might be true, but their truth depends on the evidence available. However, they are often hard to believe at first because they are very complicated and cover many different things. These theories usually fit together well and are connected to other similar ideas. They are often designed to avoid being proven wrong, either because there is no evidence against them or not enough evidence to support them.
Psychologists sometimes link an interest in conspiracy theories to certain mental health conditions, such as paranoia, schizotypy, narcissism, or insecure attachment. They may also be linked to a type of thinking called "illusory pattern perception," which is when people see patterns in random events. However, current scientific research shows that most people who believe in conspiracy theories are not mentally ill. Instead, they may be overusing natural human tendencies, such as a tendency to feel anxious or to notice possible threats, which likely developed over time as part of human evolution.
Alternative history theories
Some theories suggest that the dates of historical events may have been changed on purpose. One example is the phantom time hypothesis, created by German researcher Heribert Illig. In 1991, Illig claimed that 297 years were added to the calendar by people like Pope Sylvester II to place themselves at the start of a new millennium.
A similar idea, called the new chronology, was developed by Russian researcher Anatoly Fomenko. He believes that history is much shorter than most people think, and that many historical records were made up while real documents were destroyed for political reasons. Some people who support this theory include chess player Garry Kasparov.
New Zealand was first settled by the Māori, who came from Polynesia around the 14th century AD.
The Moriori were a group of Polynesians who moved from the New Zealand mainland to the Chatham Islands in 1500 AD. Some 19th-century historians thought the Moriori were a civilization that lived before the Māori. Some people still believe this idea, even though it has been proven false.
Māori stories describe groups like the patupaiarehe as living in New Zealand before the Māori arrived. Other theories suggest that groups such as the Chinese or Spanish may have settled in New Zealand earlier.
People who support these theories often use unreliable archaeological evidence. For example, some claimed that Kiore rat fossils found under volcanic ash from the Taupō eruption could not be found in other places. Others have claimed that natural rock formations, like the Kaimanawa Wall, look like pyramids.
Another theory claims that world governments have hidden proof of an ancient civilization called Tartaria. This civilization, which had access to free energy and included giants, was supposedly destroyed in the 1800s by a large flood. The flood is said to have buried the remains of this civilization.
Aviation
Many conspiracy theories are related to air travel and planes. Events like the 1955 bombing of the Kashmir Princess, the 1985 Arrow Air Flight 1285 crash, the 1986 Mozambican Tupolev Tu-134 crash, the 1987 Helderberg disaster, the 1988 bombing of Pan Am Flight 103, and the 1994 Mull of Kintyre helicopter crash, as well as certain aircraft technologies and reported sightings, have led to theories about wrongdoing that differ from official conclusions.
This theory about black helicopters began in the United States in the 1960s. The John Birch Society promoted it, claiming that a United Nations force would arrive in black helicopters to control the U.S. A similar idea about "phantom helicopters" appeared in the United Kingdom in the 1970s. The theory returned in the 1990s during President Bill Clinton’s time and was strongly promoted by writer Jim Keith in his book Black Helicopters Over America. By the 2000s, the term "black helicopters" became a way to describe anti-government conspiracy theories that go beyond what is believable, such as those shared by militia groups and some guests on television shows hosted by Glenn Beck.
Also known as SLAP (Secret Large-scale Atmospheric Program), this theory claims that water condensation trails ("contrails") from planes contain chemical or biological agents, or mixtures of aluminum, strontium, and barium, under secret government policies. About 17% of people worldwide believe the theory is true or partly true. In 2016, the Carnegie Institution for Science published the first peer-reviewed study on the chemtrail theory. Out of 77 scientists who participated, 76 said there was no evidence to support the theory or noted that chemtrail supporters use poor data.
The crash of Korean Air Lines Flight 007 by Soviet jets in 1983 has drawn many conspiracy theories. These include claims that the flight was part of a planned espionage mission, that the U.S. government covered up the event, or that the passengers’ remains were eaten by giant crabs.
The disappearance of Malaysia Airlines Flight 370 in Southeast Asia in March 2014 led to many theories. One suggests the plane was hidden and later used as Flight MH17 in the same year to be shot down over Ukraine for political reasons. American theorist James H. Fetzer blamed then-Israeli Prime Minister Benjamin Netanyahu for the disappearance. Historian Norman Davies claimed hackers remotely took control of a Boeing Uninterruptible Autopilot system on the plane, steering it to Antarctica.
Malaysia Airlines Flight 17 was shot down over Ukraine in July 2014. This event led to many alternative theories. These include claims that the plane was actually Flight MH370, that the Ukrainian Air Force shot it down to blame Russia, that it was part of a plan to hide information about HIV (seven disease specialists were on board), or that the Illuminati or Israel was responsible.
Business and industry
In 2010, a serious accident occurred on an oil rig in the Gulf of Mexico. Some people have suggested that the accident was caused by sabotage, either to support environmental goals or by an attack from North Korean or Russian submarines. These ideas were discussed or promoted by a US radio host named Rush Limbaugh.
Another theory suggests that the Coca-Cola Company changed its product formula to a lower quality, called New Coke, with the goal of increasing demand for the original product or allowing the original formula to return later with cheaper ingredients. The president of Coca-Cola at the time, Donald Keough, denied this claim. He said, "The truth is, we're not that dumb, and we're not that smart."
Deaths and disappearances
In ancient times, many conspiracy theories spread about the death of the Roman emperor Nero, who died by suicide in 68 AD. Some stories claimed Nero had faked his death and was hiding, planning to return to power. These stories often said he fled to the East, where he remained influential. Other theories suggested Nero would return from the dead to reclaim his throne. Early Christians feared his return because he had previously persecuted them. The Book of Revelation may hint at these ideas by describing a head that was killed but later came back to life.
Many conspiracy theories arose about the assassination of John F. Kennedy in 1963. Vincent Bugliosi estimated over 1,000 books had been written about the event, with at least 90% supporting the idea that a conspiracy was involved. Because of this, the assassination is often called "the mother of all conspiracies." Many people and groups, including the CIA, the Mafia, Vice President Lyndon B. Johnson, Fidel Castro, the KGB, or combinations of these, have been accused of involvement. Some claim the U.S. government intentionally hid important information after the assassination to hide the conspiracy.
Conspiracy theories about the assassination of Charlie Kirk were shared online. Political consultant Roger Stone said the attack seemed like a professional hit by a foreign government, rogue elements of the U.S. government, or a terrorist group. One theory, promoted by Russian media RT, claimed people near Kirk made unusual gestures before his death. Russian officials, including former president Dmitry Medvedev, speculated on social media that Kirk’s killing might be linked to U.S. support for Ukraine, as Kirk had criticized Western aid to Ukraine. Some theories falsely linked the event to Israel, with Israeli media stating these claims are based on antisemitism. Some people connected the assassination to the Israeli Mossad or to Kirk’s comments about the Epstein files. An Infowars host claimed Kirk believed Israel would kill him if he opposed them. Tucker Carlson faced accusations of antisemitism for suggesting Jews or Israel were responsible. He compared Kirk’s death to Jesus Christ’s death, saying powerful people killed Jesus for telling the truth. Israeli Prime Minister Benjamin Netanyahu rejected these theories, calling them "insane" and denying any Israeli government involvement.
On 17 December 1967, at about 12:20 pm, then-Prime Minister of Australia Harold Holt disappeared while swimming at Cheviot Beach, near Portsea, Victoria. While it is believed he drowned, his death remains one of Australia’s greatest unsolved mysteries and has led to many conspiracy theories. These theories have been criticized by the public and members of Holt’s family.
In 2007, television presenter Ray Martin hosted a special called Who Killed Harold Holt?, which aired on the Nine Network. The program explored many theories about Holt’s disappearance, giving some support to the idea that he committed suicide. Before the program aired, Holt’s biographer, Tom Frame, called the theories "unjustified and contrary to all the evidence," while Holt’s son, Sam, said he was "amazed" that false theories were still being shared.
One theory claims Holt was a spy for the Chinese government and that he "pretended to drown," with Chinese frogmen using a submarine to take him to China. This theory suggests the Australian Security Intelligence Organisation (ASIO) covered up evidence. The idea was first promoted in a 1983 novel by British writer Anthony Grey, which caused controversy in Australia. Other theories suggest Holt was assassinated by North Vietnam or the U.S. Central Intelligence Agency (CIA).
The deaths of famous people often lead to conspiracy theories, including the assassination of U.S. president Abraham Lincoln, Martin Luther King Jr., Mustafa Kemal Atatürk, Eric V of Denmark, Dmitry Ivanovich, Sheikh Rahman, Yitzhak Rabin, Zachary Taylor, George S. Patton, Diana, Princess of Wales, Dag Hammarskjöld, Kurt Cobain, Michael Jackson, Marilyn Monroe, Tupac Shakur, Wolfgang Amadeus Mozart, John Lennon, Jimi Hendrix, the Notorious B.I.G., Pope John Paul I, Jill Dando, Olof Palme, Linkin Park member Chester Bennington, Paul Walker, biological warfare expert David Kelly, Haitian president Jovenel Moïse, Indian freedom fighter Subhas Chandra Bose, and Bollywood star Sushant Singh Rajput.
Some theories claim deaths were hidden. For example, the "Paul is dead" theory suggests Paul McCartney died in a car accident in 1966 and was replaced by a look-alike boy from Scotland named William Shears Campbell, who was also called Billy Shears. The Beatles supposedly hinted at this in songs like "Revolution 9" and "Strawberry Fields Forever," as well as on album covers. Another theory, popular in Nigeria, claims former president Muhammadu Buhari died in 2017 and was replaced by a look-alike Sudanese person. Some fans of Avril Lavigne believe she died and was replaced by a look-alike named Melissa. A similar theory claims U.S. First Lady Melania Trump was replaced by someone else.
Some theories claim deaths were faked. For example, it is said that Elvis Presley’s death was not real, and Adolf Hitler survived World War II and fled to the Americas, Antarctica, or the Moon. The Soviet Union under Joseph Stalin promoted these Hitler survival theories as part of a disinformation campaign.
The disappearance of a person, often presumed dead, can also lead to conspiracy theories. For example, theories about the 1974 disappearance of Lord Lucan after his family’s nanny was murdered include claims that his body was fed to tigers at a zoo. Many theories also surround the 2007 disappearance of English girl Madeleine McCann.
The murder of Democratic National Committee employee Seth Rich led to right-wing conspiracy theories, including claims that Rich was involved in leaking DNC emails in 2016.
Economics and society
The New World Order theory claims that a group of international leaders control governments, businesses, and media, aiming to take over the world. These leaders are said to be involved in major wars, secret events, and economic changes over the past two centuries.
This theory is linked to groups like the Illuminati, Jewish communities, certain governments and companies, organizations such as the World Economic Forum, and secret groups like Bohemian Grove and Skull and Bones. Some believe famous musicians, including Beyoncé and Whitney Houston, are connected to this group. People who study these theories include Mark Dice and David Icke.
Theorists say that movies, books, and other media sometimes include hidden messages about future events, such as fake disasters or new technologies. These messages are thought to prepare people to accept such events. Examples of this idea include claims about the September 11 attacks, the COVID-19 pandemic, and events in movies like Die Hard and The Simpsons.
George Soros, a Hungarian-American investor, has been the subject of conspiracy theories since the 1990s. He has given away about $11 billion in grants to support political, social, and educational causes. However, some theories claim he controls much of the world’s wealth and funds groups like antifa for harmful purposes. These ideas have been promoted by figures such as Donald Trump and Viktor Orbán. These theories are sometimes connected to antisemitic beliefs.
Conspiracy theories about the Freemasons began in the 18th century. Some say the Freemasons control parts of countries’ economies or courts and were involved in events like the sinking of the Titanic or the crimes of Jack the Ripper. American inventor Samuel Morse wrote about these theories in 1835. These ideas are sometimes linked to antisemitic theories.
In Turkey, conspiracy theories became common during the leadership of the Justice and Development Party and Recep Tayyip Erdoğan. In 2014, Erdoğan used the term "mastermind" to describe a hidden group, possibly linked to the United States, that he claimed was working against Turkey. He and the newspaper Daily Sabah said groups like the Islamic State, the Kurdistan Workers’ Party, and supporters of Fethullah Gülen were attacking Turkey together.
In 2017, Ankara Mayor Melih Gökçek claimed that earthquakes in Çanakkale were caused by foreign powers to harm Turkey’s economy. Another example was when the newspaper Yeni Akit said that ripped jeans were a secret way for foreign agents and their allies in Turkey to communicate.
Espionage
There are conspiracy theories that claim Israel uses animals for secret missions or to harm people. These ideas are sometimes linked to theories about Zionism, a movement connected to Jewish people. Some theories focus on shark attacks in Egypt in 2010, Hezbollah's claims that eagles were used for spying, and the 2011 discovery of a griffon vulture carrying a satellite tracking device labeled as Israeli.
Some people, like former MI5 officer Peter Wright and Soviet defector Anatoliy Golitsyn, have claimed that British prime minister Harold Wilson was secretly working for the KGB, a group from Russia. Historian Christopher Andrew has noted that many people were misled by Golitsyn's stories.
Conspiracy theories about Malala Yousafzai are common in Pakistan. Some of these ideas began with a 2013 joke article in Dawn. These theories suggest Malala is a spy for Western countries, or that her 2012 attack by the Taliban was planned by her father, the CIA, and actor Robert de Niro pretending to be an Uzbek doctor.
Ethnicity, race and religion
Antisemitism, or hatred toward Jewish people, has included conspiracy theories since the Middle Ages. In medieval Europe, many believed Jews poisoned wells, caused Jesus's death, and used Christian blood in rituals. In the 19th century, some claimed Jews or Freemasons were plotting to control the world. False evidence, like the 1903 book The Protocols of the Elders of Zion, falsely accused Jews of planning to dominate the world. These ideas influenced Adolf Hitler's beliefs. Today, similar theories suggest Jewish people control banking, Hollywood, or the U.S. government, all claiming secret plans to create global tyranny.
Holocaust denial, which claims the Nazi killing of Jews was a hoax, is also considered an antisemitic conspiracy. People like Iranian president Mahmoud Ahmedinejad and author David Irving have spread these lies.
Reptilian conspiracy theories, often linked to alien studies, have connected Jewish people to secret control of the world. Author David Icke claimed Jewish leaders like the Rothschild family were reptilian shapeshifters. Critics say these ideas are antisemitic, though Icke denies this. Some far-right groups suggest Jewish people were created by aliens in a space battle.
In Azerbaijan, some claim Armenians secretly control politics. President Ilham Aliyev and others have accused Armenians of plotting against Azerbaijan. In Turkey, officials have said Armenian media is controlled by Armenians. Writer Samuel Weems falsely claimed the Armenian genocide was a fraud to steal money. Filmmaker Davud Imanov accused Armenians of working with the CIA to destroy the Soviet Union.
In Iran, the Baháʼí Faith, a religious group, has been falsely accused of being agents for foreign governments. A book called The Memoirs of Count Dolgoruki falsely claims Baháʼís want to destroy Islam. These claims have no real evidence.
Since the 16th century, some have claimed Catholics, or followers of the Roman Catholic Church, are involved in secret plots. The 17th-century Popish Plot falsely accused Catholics of trying to kill the British king. Others, like William Blackstone and Samuel Morse, claimed Catholics were a threat. Some say the Pope is the Antichrist, a figure from Christian prophecies.
In 1853, Alexander Hislop wrote The Two Babylons, claiming the Catholic Church is based on ancient pagan religions. He said holidays like Christmas and Easter are pagan festivals. Scholars say this is false, but some groups still believe it. The Jehovah's Witnesses published parts of Hislop's book until the 1980s.
Fears about Catholics taking over the U.S. began with large Catholic immigration in the 1800s and were spread by the Ku Klux Klan. Political figures like Al Smith and John F. Kennedy faced suspicion. Pope John Paul I's sudden death in 1978 and Pope Benedict XVI's 2013 resignation led to conspiracy theories about secret networks.
Christian prophecies about the end times have inspired theories about the Antichrist, a figure who will rule the world. Many people, including Frederick II, Napoleon, and Donald Trump, have been falsely called the Antichrist.
Some believe witch trials in the 1500s–1700s were meant to stop pagan religions. Far-right groups claim Christianity was created by Jews to harm the Aryan race, a term used to describe people of European descent.
In the 1930s–1940s, Nazi leader Heinrich Himmler studied witch trials to spread anti-Christian propaganda, claiming the Church had suppressed a Germanic religion.
After the 9/11 attacks, anti-Islamic theories grew. "Love Jihad" falsely claims Muslim men try to convert women through fake love. The "Eurabia" theory suggests Muslims are trying to take over Europe. Some said President Barack Obama was secretly Muslim.
Bible conspiracy theories claim parts of the New Testament are false. A book called The Holy Blood and the Holy Grail (1982) falsely said Jesus and Mary Magdalene had children, with descendants in Europe. This book was debunked, but it inspired other conspiracy ideas.
Fandom, celebrity relationships, and shipping
Many people believe in stories that suggest fans of a group want two celebrities to be in a romantic or sexual relationship, which is called "shipping." Some of these stories claim that the children of married or partnered celebrity couples are not real. People who support the idea that two celebrities of the same gender are in a relationship often say they are helping promote LGBTQ+ rights by believing the celebrities are hiding their true feelings because of an industry that does not support LGBTQ+ people. Groups that talk about celebrity relationships are mostly made up of women.
The term "Gaylor" is an uncommon idea that suggests the American singer Taylor Swift is gay or not heterosexual.
"Larries" is a group of fans who believe two members of the boy band One Direction, Harry Styles and Louis Tomlinson, are secretly a couple. These fans claim that Styles and Tomlinson have been hiding their relationship because of their management company, even though Styles, Tomlinson, their friends, and their family have said this is not true.
Government, politics, and conflict
In the modern era, political conspiracy theories are often shared through fake news on social media. A 2017 study by the Shorenstein Center found that "misinformation is mostly a problem among people on the right." Political conspiracy theories can involve broad topics like wars and international groups, or they can focus on specific events, such as the belief in Kitchener, Ontario, that the 118th Battalion, a British military unit stationed there during World War I, remained in the area after the war and influenced local politics for years.
BlueAnon is a collection of left-wing conspiracy theories that claim Donald Trump is involved in complex plans to control the United States government.
Crisis actors are people who act as victims in training exercises for first responders. Some conspiracy theories suggest that real-life disasters, such as mass shootings, are staged with actors pretending to be victims and their families.
Conspiracy theories about the Illuminati, a secret society from the 18th century, began in the late 19th century when some European Catholics believed the group caused the French Revolution. In the 1960s, a group called the Discordians created fake letters about the Illuminati for a magazine called Playboy.
False flag operations are secret actions designed to look like other groups are responsible. Some claims about these operations have been proven true or are debated by historians, such as the 1933 fire in the German parliament. Other unverified claims appear in conspiracy theories.
Unsubstantiated claims about false flag operations have been linked to events like the bombing of Pearl Harbor, the Oklahoma City bombing, the 2004 Madrid train bombings, the 1964 Gulf of Tonkin incident, and the Euromaidan massacre. The rise of groups like ISIS and Boko Haram has led to theories that they were created by the U.S., CIA, Mossad, or Hillary Clinton.
The September 11, 2001, terrorist attacks have inspired many conspiracy theories. Some suggest the use of missile or hologram technology, while the most common theory claims the Twin Towers collapsed due to controlled demolitions. This theory has been rejected by engineers and the 9/11 Commission.
The 2012 Sandy Hook Elementary School shooting in Newtown, Connecticut, led to theories that the event was staged to support gun control laws. Some people, including Alex Jones, claimed actors were involved. Families of victims faced harassment from conspiracy theorists, leading to legal actions for defamation. Rush Limbaugh falsely linked the shooter, Adam Lanza, to the Mayan Calendar.
The "Clinton body count" conspiracy theory, promoted by Newsmax publisher Christopher Ruddy, claims that former President Bill Clinton and his wife, Hillary Clinton, killed over 50 people. This theory dates back to the 1990s, when a film called The Clinton Chronicles accused Bill Clinton of crimes, including murder.
The 2019 death of Jeffrey Epstein, a billionaire with ties to Bill Clinton and Donald Trump, has led to conspiracy theories about his death.
The 2017 Las Vegas shooting, the deadliest mass shooting in U.S. history, has also inspired conspiracy theories. Some claim the shooter used a machine gun instead of semi-automatic weapons, while others suggest the government was involved to justify banning bump stocks. Investigations have debunked these claims, but they continue to spread.
The U.S. Federal Emergency Management Agency (FEMA) is the subject of theories that it is building concentration camps to prepare for martial law and genocide.
In South Africa, members of the African National Congress (ANC) have promoted conspiracy theories about the CIA and white supremacists. In 2014, a government official accused Public Protector Thuli Madonsela, without evidence, of being a U.S. agent.
Barack Obama has been the focus of many conspiracy theories. A 2009 film by Alex Jones claimed his administration was controlled by a wealthy elite. The "birther" theory, which falsely claimed Obama was not born in the U.S., persisted despite evidence, including his birth certificate and newspaper announcements from 1961. Promoters of the theory included dentist-lawyer Orly Taitz and former President Donald Trump. Other theories falsely claimed Obama was secretly a Muslim.
The 2012 Benghazi attacks, in which Islamist terrorists attacked U.S. facilities in Libya, led to conspiracy theories that the Obama administration orchestrated the event for political reasons. Senator Rand Paul claimed the government's response to the attack was meant to hide a secret CIA operation.
The Frankfurt School, a group of intellectuals from the 1930s, has been accused of promoting communism in capitalist societies. The term "Cultural Marxism" has been used by conservative groups like the Tea Party and by Norwegian mass murderer Anders Behring Breivik.
"Woke" conspiracy theories claim that progressive social justice movements are part of an elite plan to destroy Western culture, capitalism, and traditional values. These theories often link to the "Cultural Marxism" idea, which falsely claims Jewish intellectuals from the Frankfurt School aimed to destabilize Western civilization. This theory has been used to justify far-right violence, including by Breivik.
These theories reject the existence of systemic racism and argue that diversity and inclusion efforts harm white people. They combine anti-feminism, white supremacy, and anti-intellectualism to argue that progressive ideas must be removed to "restore" society. The theories frame "woke" ideology as a continuation of the Cultural Marxism conspiracy, blaming Jewish intellectuals for societal issues.
Medicine
A study from 2013, done by the University of Chicago, found that nearly half of Americans believe at least one medical conspiracy theory. Thirty-seven percent of those surveyed believed the Food and Drug Administration hides natural cures because of pressure from the pharmaceutical industry. Kevin Trudeau, a person convicted of fraud, has promoted similar conspiracy theories.
Scientists have found proof that HIV was passed from monkeys to humans in the 1930s. However, some evidence suggests that the KGB spread an idea in the 1980s that HIV was created by the CIA. This idea, along with similar claims about Ebola, has been promoted by people such as actor Steven Seagal, leader of the Nation of Islam Louis Farrakhan, and former South African president Thabo Mbeki. Other theories claim that pharmaceutical companies help create conditions like ADHD, HSV, and HPV.
Many conspiracy theories exist about the origin and purpose of the SARS-CoV-2 virus and how it spreads. Some say the virus was made in a lab, that it was a bioweapon developed by China or the United States, or that it is part of a Jewish plan to force mass vaccinations or sterilizations. Others claim it is linked to Muslim groups, population control efforts, or 5G mobile networks.
Water fluoridation is the process of adding fluoride to public water supplies to reduce tooth decay. While many dental groups support this practice, some people believe it is a way to get rid of industrial waste or to hide poor dental care for low-income communities. In the 1960s, the John Birch Society claimed fluoridation was a communist plan to weaken the American population.
Some people claim the pharmaceutical industry is hiding a link between vaccines and autism. This idea began after a fake study published in Britain in 1998 by a discredited doctor named Andrew Wakefield. The anti-vaccine movement, supported by people like Rob Schneider, Jim Carrey, former U.S. president Donald Trump, and Robert F. Kennedy Jr., has caused more infections and deaths from diseases like measles and COVID-19 in countries such as the U.S., Italy, Germany, Romania, and the UK. In Nigeria and Pakistan, vaccine conspiracy theories have been common since at least 2003. These theories sometimes say vaccines are part of a secret plan against Islam and have been linked to violence at vaccine clinics in both countries.
Outer space
Scientific space programs are a topic of interest for some people who believe in conspiracy theories. One common idea is that the United States' Moon landings were not real events but were instead created by NASA in a movie studio. Some people even claim that famous film director Stanley Kubrick was involved in making these fake events. The Soviet space program has also been the subject of theories, with some suggesting that the government hid information about failed space missions. A more recent theory, which came up after hacker Gary McKinnon's actions, claims that a secret group of crewed spacecraft exists and is controlled by the United Nations.
Conspiracy theorists have also suggested that organizations like NASA are hiding the existence of a large planet in our Solar System called Nibiru or Planet X. This planet is said to come close to Earth and cause destruction. Predictions for when this might happen include the years 2003, 2012, and 2017. This idea began with a book titled The 12th Planet (1976) written by Zecharia Sitchin, a Russian-American author. Later, Nancy Lieder expanded the theory, and it was promoted by David Meade, a U.S. conspiracy theorist. The theory gained more attention before the solar eclipse on August 21, 2017. Other people, such as Terral Croft and YouTube pastor Paul Begley, also claimed Nibiru would appear in 2017.
Many conspiracy theorists focus on questions about alien life. For example, some believe the government covered up events related to the Roswell incident or activities at Area 51. Since the 1960s, reports of dead cattle with missing body parts and drained blood have been found worldwide. These events have led to theories about aliens or secret government and military experiments. Linda Moulton Howe, an author who wrote Alien Harvest (1989), is one person who has studied these claims.
Many conspiracy theories are influenced by the work of Zecharia Sitchin, who believed that the Anunnaki from Sumerian mythology were actually extraterrestrial beings who arrived on Earth about 500,000 years ago to mine gold. In his 1994 book Humanity's Extraterrestrial Origins: ET Influences on Humankind's Biological and Cultural Evolution, Arthur Horn suggested the Anunnaki were reptilian aliens that drank blood and could change their shape. This idea was later expanded by British conspiracy theorist David Icke, who claimed that people like the Bush family, Margaret Thatcher, Bob Hope, and the British royal family were or had been controlled by these creatures. Critics of Icke have argued that his "reptilian" theory might be linked to antisemitism, but Icke denies this.
Science and technology
A climate change conspiracy theory usually claims that the science about climate change was made up or changed for political or financial reasons, such as higher taxes, rules about daily life, or more government control. People like former U.S. President Donald Trump, U.S. Senator James Inhofe, British journalist Christopher Booker, and Viscount Christopher Monckton have supported these ideas. Author Michael Crichton wrote a book based on this idea.
Many theories involve real or claimed weather-control projects. One theory says that HAARP, a U.S. government-funded radio research program, is secretly used to control the weather. Some people have blamed HAARP for natural disasters like Hurricane Katrina in 2005 and Hurricane Helene and Milton in 2024. Others say HAARP caused earthquakes, including the 2010 Haiti earthquake, the 2011 Tōhoku earthquake and tsunami, the 2013 Saravan earthquake, and the 2023 Turkey–Syria earthquakes. Some theories also claim HAARP is linked to mind-control technology. Other theories focus on cloud-seeding technology, such as the idea that the British military’s Project Cumulus caused the 1952 Lynmouth Flood in England, or that California droughts and the 2010 Pakistan floods were caused by secret weather-control projects.
In the 1950s and 1960s, real U.S. research into chemical interrogation and mind-control methods led to conspiracy theories, such as Project Monarch. These theories grew after CIA Director Richard Helms ordered all files about the project to be destroyed in 1973. Some theories claim the 1978 Jonestown tragedy was connected to an MKUltra experiment.
Flat Earth theory began in 19th-century England, even though scientists had long known the Earth is round. In recent years, American software consultant Mark Sargent promoted this idea through YouTube videos. Flat Earth believers say the Earth is flat, not round, and that evidence of its shape has been hidden or faked. They often accuse NASA of being involved. Other claims say GPS devices trick pilots into thinking the Earth is round.
Radio frequency identification (RFID) chips, used to track pets, have led to theories that these chips are secretly implanted in humans. Former town councilor Simon Parkes from England promoted this idea, which is sometimes linked to theories about vaccines, electronic banking, and the Antichrist.
Some theories claim certain technologies and energy sources are being hidden. These include the Vril Society Conspiracy, claims that fossil-fuel companies stopped electric cars from being used (as shown in the 2006 documentary Who Killed the Electric Car?), and the Phoebus cartel, which was accused of making light bulbs last shorter. Other theories say governments or groups have hidden technologies like perpetual motion and cold fusion. People who support these ideas include Thomas Henry Moray, Eugene Mallove, and Stanley Meyer, who was later convicted of fraud.
Conspiracy theories often focus on military technology, real or imagined. These include the alleged Philadelphia Experiment, a claim that a U.S. Navy ship was made invisible; the Montauk Project, a supposed government program about mind control and time travel; and the "tsunami bomb," which some say caused the 2004 Indian Ocean tsunami.
A theory from a Venezuelan TV station, ViVe, said the 2010 Haiti earthquake was caused by a secret U.S. "earthquake weapon."
Some people believe government agents use directed-energy weapons and electronic surveillance to bother individuals. They point to research on psychotronic weapons, the Cuban health attacks, and the microwave auditory effect as evidence. Over 10,000 people say they are "targeted individuals," a topic covered in TV shows like Conspiracy Theory with Jesse Ventura and In Search of… on the History Channel.
The "Dead Internet" theory says most online content is created by bots and not real people.
Another theory claims smartphones with microphones listen to private conversations and use that data to show targeted ads.
Conspiracy theories about mobile phones started in the 1990s, similar to past fears about radio waves in the early 1900s. With the introduction of 5G technology in 2019, the same year the SARS-CoV-2 virus (which causes COVID-19) was discovered, many theories linked the two.
Sports
Boxing has been linked to conspiracy theories, such as the idea that the second Ali-Liston fight and the first Bradley-Pacquiao fight were not fair.
The disappearance of the Irish-bred racehorse Shergar in 1983 led some people to suggest that groups like the Mafia, the Irish Republican Army, or Muammar Gaddafi might have been involved.
The "frozen envelope theory" claims that the National Basketball Association manipulated its 1985 draft lottery to ensure Patrick Ewing joined the New York Knicks. Supporters of this idea say a lottery envelope was cooled so it could be recognized by touch. A similar "hot balls theory," proposed by Scottish football manager David Moyes, suggests that balls used in some sports draws were warmed to influence outcomes.
The 1984 Firecracker 400 at Daytona International Speedway in Florida was the first NASCAR race attended by a U.S. president, Ronald Reagan. It was also driver Richard Petty’s 200th and final career victory. Rival driver Cale Yarborough left the race early, leading some to believe the organizers may have influenced the outcome to gain positive attention for the event.
During the 1998 FIFA World Cup final, Brazilian player Ronaldo had a sudden convulsive fit. He was first removed from the starting lineup 72 minutes before the match, but was later allowed to play by Brazil’s coach, Mário Zagallo. Ronaldo performed poorly in the game, which France won. The unusual circumstances of his illness led to many questions and theories. Some people wondered if stress, epilepsy, or drugs were involved. Others questioned whether Nike, Brazil’s major sponsor, influenced the decision to let Ronaldo play.
The New England Patriots have been connected to several conspiracy theories. During their 2018 AFC Championship win over the Jacksonville Jaguars, some believed the referees helped the Patriots reach Super Bowl LII, where they lost to the Philadelphia Eagles. Sports analyst Stephen A. Smith said the Jaguars lost due to their own mistakes. Other theories surrounded the Super Bowl LI game between the Patriots and the Atlanta Falcons, with some claiming the game was unfair and others suggesting the Falcons made poor decisions that led to their loss.