20 Biggest Conspiracy Theories of the Century So Far

Health Authorities Hide Natural Cures

Big Pharma doesn’t just sell medicine, according to conspiracy theorists. The industry uses its power to hide and shelve real, natural cures all for the sake of profit. Online forums claim natural remedies for everything from diabetes to heart disease are being suppressed. Why release the cure when you can force people to keep paying for treatment? Garlic, cannabis, turmeric – you name it, someone swears it’s a miracle the FDA won’t approve. The belief exploded in the 2010s, fueled by viral documentaries and wellness influencers railing against “corporate medicine.” Scam artists take advantage of understandable distrust in health profiteering. Scientists say most of these claims collapse under scrutiny. But for millions, the idea of a hidden cure is irresistible.

Alaskan Mind Control Lab (2003)

High in the Alaskan wilderness, a field of towering antennas hums against the snow. It’s called HAARP – a real research program studying the ionosphere. But to conspiracy theorists, it’s something far darker: the center of half a dozen theories. Some believe those antennas beam frequencies straight into human brains. The government, they say, bends our thoughts to cause targeted unrest and for population control. Every protest, every sudden craze, every mass panic? Blamed on HAARP. And if that weren't enough, they say it can twist the weather too. HAARP can spark hurricanes or clear skies on command. Scientists insist it’s harmless, but the theory refuses to die.

Nibiru Cataclysm

For decades, a certain subset of the online fringe have pitched a unique apocalyptic vision. These doomsday prophets have warned of a rogue planet barreling toward Earth. They call it Nibiru – Planet X – hidden beyond the reach of telescopes, cloaked by government lies. When it finally appears, believers say it’ll flip Earth’s poles, drown cities, and tear civilization apart. The theory roared back to life in the early 2000s. It hitched a ride with every apocalyptic craze from Y2K to the Mayan 2012 scare. NASA insists Nibiru doesn’t exist, but online? Every earthquake, every climate disaster, every blood-red moon fuels whispers that the end is coming – and no one’s telling us.

Earth Was Sucked Into a Black Hole

What if the end of the world already happened – and no one noticed? That’s the claim behind one of the internet’s strangest theories: that Earth was swallowed by a black hole sometime in the last two decades. Believers point to the Mandela Effect, strange physics anomalies, and the growing sense that “something feels off” since 2012. In this view, we’re not just orbiting the sun – we’re trapped inside a singularity, living out our days in a warped simulacrum of reality. Mainstream scientists say the idea probably doesn’t hold up. For some, though, it explains why our world seems to have gone mad.

California Wildfires

When California burns, conspiracy theories ignite just as fast. Some blame secret military weapons or “energy beams.” Remember the infamous “Jewish space laser” claims? Others insist the fires are deliberate, part of a scheme to clear land for elites or force people from their homes. After the Paradise inferno and Maui’s devastation, TikTok swarmed with shaky videos. Untouched trees beside charred houses were “proof” of targeted destruction, not just random acts of fate. Scientists point to drought, high winds, and failing power lines. But online, every spark looks suspicious. Every wildfire becomes another battle in a made up shadow war.

The Dead Internet Theory

Ever feel like the internet doesn’t feel quite right anymore? Like things have just persistently gone downhill over the last decade? According to the Dead Internet Theory, most of the web’s content – social media posts, news articles, comments, maybe even this video – is generated by AI or government bots. In this view, the living, chaotic internet of the 2000s quietly died. In its place, corporations and governments swapped it for an algorithmic ghost town built to manipulate us. Every viral meme, every trending topic, every sudden outrage you have seen is manufactured. Experts dismiss it as paranoia, but in an age of deepfakes and bot farms, the line between truth and fiction has never felt thinner.

Mass Shootings Are Fake

After the Sandy Hook tragedy in 2012, a chilling new conspiracy spread oInline: that the massacre – and countless others – never happened. Alex Jones used his “Infowars” platform to claim grieving parents were “crisis actors.” His followers spent years harassing and threatening families who suffered grievous losses. Soon, every new shooting – Parkland, Uvalde, Las Vegas – was branded a government “false flag." The theory warped public trust and deepened America’s divisions. In 2022, Jones was finally held accountable, ordered to pay hundreds of millions to the Sandy Hook families. But the damage was already done. For many, the lie will never die.

The Great Replacement Theory

In 1973, a French novel painted the picture of a rightwing nightmare: migrants flooding the West, overwhelming white populations, and destroying their culture. It was bigoted fiction – but extremists treated it like prophecy. Over decades, that story curdled into the Great Replacement Theory. Its adherents believe in a secret plot by leftwing elites and Jews.Their alleged goal is to erase white identity through mass immigration. Once whispered on fringe forums, it’s now echoed in political speeches, cable news, and viral posts. Worse: it’s turned deadly. The 2018 Tree of Life Synagogue shooter cited it. So did the Buffalo gunman in 2022. A lie born in fiction now fuels real violence.

9/11 Truth Movement

September 11, 2001 changed the face of the 21st century. Al-Qaeda terrorists committed a mass hijacking, flying planes into the Twin Towers and the Pentagon. Thousands died that day, but millions would go on to suffer the consequences in the wars to follow. But in the dark corners of the web, another story took hold: that 9/11 was an inside job. Online forums dissected grainy footage frame by frame, questioning collapsing steel, missile strikes, and controlled demolitions. Theories snowballed, implicating everyone from the Bush administration to shadowy “deep state” actors. Even as evidence pointed to Al-Qaeda – and Saudi complicity – the movement refused to die. More than two decades later, it’s still echoing in politics and campaigns.

#Stopthesteal

The 2020 U.S. presidential election was called the “most secure in American history.” But to millions of Trump supporters, that was just the first lie. Fueled by baseless claims of voter fraud, the “Stop the Steal” movement surged online – mostly among the same crowd that believed nonsense claims about Obama’s birth certificate. It culminated with an attempted insurrection, when supporters of #stopthesteal violently stormed the U.S. Capitol on January 6, 2021. The attack left officers battered, lawmakers scrambling, and the nation reeling. In its wake, two competing realities hardened – one documented by congressional hearings, the other broadcast on partisan media. Years later, the fractures remain.

Secret Headquarters at Denver Airport

The Denver Airport is the largest airport in the United States by a wide margin. To give you an idea of its size, it’s more than 1.5 times larger than Manhattan. If you’re wondering why it’s so big, some might say it's because it’s the base of the secret organization pulling the strings from the shadows, the Illuminati. Others believe that it was built by neo-Nazis or that the airport secretly houses shapeshifting lizards in the tunnels below its busy hub. For its own part, the airport hasn’t done much to repel these theories and even leans into them, going so far as to put up signs that say it’s “remodeling the lizard people’s lair.”

Fake Snow

We have TikTok to thank for this next theory. Just this year someone had the idea to put a lighter to a snowball, and they were surprised to find that it didn’t melt but burned instead. People began taking to social media and declaring that the snow was fake, manufactured by none other than billionaire Bill Gates in conjunction with the Chinese government to somehow benefit from this. The process is actually just sublimation, which is when a solid skips turning into a liquid and goes straight to a gas, but that’s not nearly as fun.

The FDA Has the Cure for Cancer

This next theory is logical in at least one premise. It is true that Big Pharma, or the global pharmaceutical industry, has a reputation for hiking up their prices to make a profit. Conspiracy theorists therefore latched onto the idea that it actually has discovered a cure for cancer already but withholds it from the public in order to continue selling overpriced drugs. We’re not going to defend Big Pharma, but we are going to point out that keeping a secret of that caliber is not only supervillain level stuff, but would also be next to impossible to manage.

Chemtrails

One of the more popular conspiracies on the list, many people believe that the streaks left behind by airplanes are chemicals designed for a variety of functions, including sterilization, mind control, or weather control. Theorists point towards these exhaust trails as visual evidence of this poisoning, but science again explains this phenomenon, which is actually just caused by gases cooling enough to condense into clouds. If a mass conspiracy was at hand, any researchers or universities would be eager to unveil such a massive cover up, but so far no one has blown the whistle.

Vaccines Cause Autism

This conspiracy has always been popular but experienced a resurgence for obvious reasons since the emergence of COVID-19. Many people believe that vaccines cause a variety of disorders, especially autism. This conspiracy was born by a since retracted 1998 paper that linked the two, but Britain’s General Medical Council determined that lead scientist, Andrew Wakefield, acted unethically towards the children of the study and accepted money from lawyers who were at the time in dispute with vaccine manufacturers. Nevertheless, a mistrust of vaccines has continued to plague the world despite the fact that many are mandatory to attend school in the first place.

The Earth Is Flat

Nowhere near a new theory, it nonetheless has remained popular in the 21st century despite photographic evidence to the contrary. Some prominent celebrities have backed the conspiracy, claiming that the Earth is not a sphere, like the sun and moon are, but rather it is flat and stationary in space. The scientist Eratosthenes actually measured the Earth’s circumference around 240 BC by measuring the angle of shadows on the surface of the Earth. However, even with contemporary science, the belief remains. Other theorists contend that the Earth is not flat but hollow, with an entire civilization living inside our planet.

5G Causes Diseases

5G refers to the 5th generation of broadband cellular network technology. This has us asking what’s so sketchy about the number 5? No one had any issues with 4G, but 5G seems to be the harbinger of diseases like the coronavirus according to some. Conspiracy theorists claim that 5G wireless technology in cell phones somehow transmits deadly diseases, such as cancer, to those around them. Part of the belief is somewhat rational, as 5G does emit radiation, albeit a harmless kind. Nonetheless, some have jumped to the conclusion that 5G is the culprit of COVID, going so far as to tear down and vandalize 5G towers.

COVID-19 Was Engineered by the Media

2020 was not only a breeding ground for the COVID virus, but for conspiracies surrounding the virus itself. Another conspiracy involving population control of sorts, this one says that COVID is a fabrication by the media and global elite as a way to control the population through microchips and mask mandates. These have all been proven wrong many times, but the belief persists nonetheless, partly because of the distrust of government officials. Nonetheless, COVID is a very real virus that everyone should take seriously. There is no evidence that wearing a mask will brainwash you.

QAnon

What started out as speculation on the website 4chan has devolved into a conspiracy involving pizza chains and pedophilia, blood-drinking, Satan-worshipping politicians, and President Donald Trump as a savior. The theory went that the bloodthirsty pedophilic elite – mainly Democrats of course – would be outed by Trump and arrested en masse, but every prediction so far has failed to come true. The conspiracy was kept alive via anonymous online posts claiming to come from a knowledgeable insider, most of which were just word salad. It should go without saying that this theory is unproven. Still, QAnon has a very dedicated following, and dominated headlines for several years.

Jeffrey Epstein Was Killed

This might be the most widely believed conspiracy on the list, as only a small percentage of Americans believe Jeffrey Epstein took his own life, but it is nonetheless just a hypothesis due to lack of evidence. Convicted sex offender Jeffrey Epstein was found dead in his prison cell while he was awaiting trial for sex trafficking, and authorities, along with the New York City medical examiner, declared his death was caused by hanging. Due to the many mishaps by the justice system, however, many believe he was silenced by powerful people so he couldn’t talk. It’s a compelling case, but there’s nothing conclusive pointing to foul play – yet.

Which of these conspiracy theories do you think best defines this crazy era we find ourselves in together? Let us know in the comments below!