35 of the most popular conspiracy theories in the US

• All over the US, there are conspiracy theories big and small.
• UFOs are at the center of popular conspiracy theories throughout the US, especially in Roswell, New Mexico; Flora, Mississippi; and Area 51, Nevada.
• Some people believe there is more to the story around the assassinations of Martin Luther King Jr. in Memphis and President John F. Kennedy in Dallas.
• There's an organization in Alaska that studies the upper atmosphere, but there are people who believe the facility caused the Joplin, Missouri, tornado and other devastating weather events.
• Visit INSIDER's homepage for more stories.

Just as every state has its own urban legends, many have controversial conspiracy theories.

Throughout the US, there are people who believe the government, large organizations, or secretive companies are hiding the truth from the public. These conspiracists strive to uncover the "truth" behind some of the biggest news stories, from supposed UFO sightings to the JFK assassination to the Kentucky Derby.

These are the wildest and most bizarre conspiracy theories from around the US.

Some people believe the American military installation Area 51 is researching and experimenting on aliens and their spacecraft.

The famous Area 51 in the Nevada desert is a military installation at the Nellis Military Operations Area. But the base quickly became known as the most secretive military site in the world because it does not exist on any map or government website, leading many to craft conspiracy theories.

Some believe Area 51 is researching and experimenting on aliens and their spacecraft. More specifically, people think they are studying a crash that happened near Roswell, New Mexico, in 1947. Others theorize that the moon landing was staged at Area 51.

The government has said the facility is used to test experimental aircraft for the military.

Some believe that Truman Capote wrote Harper Lee's famous novel, "To Kill a Mockingbird."

Truman Capote and Harper Lee both grew up in Alabama and were childhood friends. They each went on to become celebrated authors. Capote wrote his crime story "In Cold Blood" and Lee the great American novel "To Kill a Mockingbird."

While Capote went on to write numerous books, Lee published only one other book in her lifetime, leading some to believe that Capote wrote "To Kill a Mockingbird," according to CNBC.

In a 2010 documentary, Lee's sister, Alice C. Lee, denied the accusation, saying Capote had been jealous of her sister's success.

Martin Luther King Jr. was assassinated in Memphis, but some think there is more to the story.

On April 4, 1968, Martin Luther King Jr. stepped out onto his balcony at the Lorraine Motel in Memphis, Tennessee, and was shot. The civil-rights leader died at the Memphis Hospital at 39 years old. The killer, James Earl Ray, was caught and pleaded guilty a year later. However, many people, including King's own children, do not believe Ray acted alone.

Some believe the FBI or the Ku Klux Klan were involved in the assassination and believe Ray was framed, according to NPR. The US Justice Department investigated the death on three separate occasions. Once, they concluded that there may have been a wider conspiracy, but there is no hard evidence to support it.

Roswell, New Mexico, is a famous center for UFO-focused conspiracy theories.

On July 4, 1947, Mac Brazel went out to his sheep pasture in Roswell, New Mexico, and found some unusual objects including metallic sticks, foil reflectors, and paper scraps. Since he had no idea what the objects were, he called the local sheriff who then called the Roswell Army Air Force. The pieces were swiftly taken away in armored trucks.

A few days later, the Roswell Daily Record published an article titled "RAAF Captures Flying Saucer on Ranch in Roswell Region," sparking conspiracy theories that would last decades. Many believed that the pieces found in the field were from an alien ship, even though officials said they were from a broken weather balloon.

Years later, it was discovered that the objects were part of a secret military project called Project Mogul, which aimed to eavesdrop on the Soviet Union.

Some of the most popular conspiracy theories in the US surround the Kennedy assassination.

On November 22, 1963, President John F. Kennedy was in a motorcade in Dallas, Texas, when he was struck by two bullets. He died moments later at 46 years old. Lee Harvey Oswald was arrested for the assassination of the president, and, two days later, Oswald was killed on live television.

The Warren Commission was then created to investigate the incident and concluded that Oswald acted alone. However, some believe there is more to the story. There are theories that the CIA hired Oswald because of the president's reactions to Communism and the Bay of Pigs Invasion. Others believe the Mafia, Cuba, or the Soviet Union were involved in the assassination.

When videos of the incident were released, people claimed Oswald's location made it impossible for him to have killed the president. Most recently, however, a scientist at IMSG concluded that Oswald did assassinate JFK.

There have been 2,032 Bigfoot "sightings" in Washington state.

Although there are Bigfoot sightings all over the US, Washington state has the highest number. There have been 2,032 sightings in the state, according to Newsweek.

There are a number of theories around the mythical creature. Some believe it's a ferocious beast meant to be feared and others think it's a harmless creature that wants to be left alone. There are other theories that Bigfoot is related to humans since it walks on two legs, while others think it's an extraterrestrial being.

The original 1958 footprints were a prank by a man named Ray Wallace near Bluff Creek in Northern California, according to the Smithsonian. His children revealed it was all a joke after his death in 2002.

The world's most famous UFO sighting happened in Flora, Mississippi.

February 10, 1977, is a very important day in UFO conspiracy theory history. It was the day several police officers claim to have seen a strange object hovering in the sky in Flora, Mississippi, over the top of a forest.

"It was approximately 15 to 18 feet off the ground, blue in color, kind of metallic blue, portholes around the center of it, shaped like an old spinning top kids used to use,"one of the officers said.

The officers followed the UFO until it vanished over the treeline. Years later, there seem to be two spots in the forest that measure about 15 feet each where nothing is growing, but there has never been a formal explanation.

There have been countless sightings of a Loch Ness-like monster at Flathead Lake, Montana.

In 1889, Captain James C. Kerr and his 100 passengers aboard a steamboat reported seeing a 30- to 40-foot-long creature in Flathead Lake. As of July 2018, there have been 109 sightings of the foreign creature, according to NBC Montana.

"I remember saying, 'Look, look! That's it! We're seeing it!'" one witness told NBC. "I knew immediately because the descriptions are all the same. It was like 25 feet from what we could see and humps."

Other witnesses said the creature resembles the famous Loch Ness monster with "steel black eyes" and fins.

Johnny Gosch was abducted in 1969 from Des Moines, Iowa, and conspiracies have surrounded his disappearance for years.

On September 5, 1982, Johnny Gosch, 12, vanished without a trace from Des Moines, Iowa, while on his morning newspaper run. Without any evidence or leads, the case went cold and has remained unsolved, but there have been a number of conspiracy theories about what happened to him.

Some people believe that he was forced into a child-sex ring that was operating in Nebraska. His mother, Noreen, received pictures of a man tied up in a basement, leading her to believe the theory was true, though the man in the picture could not be proved to be Gosch and there was no other evidence to prove the theory.

In 1997, Noreen said her now grown-up son visited her with his captor. She said he told her he was all right and that he was still alive, igniting even more conspiracies that he was still alive. But police could not corroborate the mother's story.

Finally, there is a conspiracy that White House reporter Jeff Gannon is Johnny Gosch because they share similar political characteristics. This theory was also never proved.

There were a lot of Mattress Firm stores in Illinois all within a few miles of one another, leading some to believe it was a money-laundering business.

In 2018, a Reddit user brought attention to the fact that there was a high concentration of Mattress Firm stores in certain areas of the US, especially in Chicago. The Reddit thread quickly went viral, with thousands sharing photos and maps that show Mattress Firm stores within .5 miles of each other and sometimes even across the street.

This led people to theorize that the retail company is a money-laundering business.

"Mattress Firm is some sort of giant money laundering scheme," one Reddit user wrote. "I remember seeing four mattress firms all on each corner of an intersection once, and there is no way there is such a demand for mattresses."

WBUR and Business Insider debunked this theory in 2018.

Some people believe that a research facility in Alaska is a mind-control lab.

In the mountains of Alaska, you can find the High-Frequency Active Auroral Research Program that helps scientists study the farthest distances of the atmosphere. The facility sits on 33 acres of land and has over 180 antennas. The antennas have collected data about Aurora Borealis, radio waves, and other atmospheric occurrences.

But some think the antennas are an experimental weapon that can control people's minds, according to the Smithsonian. Others believe it caused the Columbia space shuttle to destruct in 2003. In 2016, however, the facility held an open house so the public could see that they were not up to anything dangerous.

The Denver International Airport is well known for a number of conspiracy theories.

The Denver International Airport is twice the size of Manhattan, New York, and almost every corner of the massive transportation hub is filled with conspiracy theories. For starters, the airport was $2 billion over budget, leading some to believe it has an underground structure that is either used as bunkers or as the headquarters of the supposed world-controlling group the Illuminati.

Others believe the building was built by Neo-Nazis because markers and plaques around the airport say it is funded by "The New World Airport Commission," but no information can be found about the organization anywhere. Some even say the runways are laid out like a swastika if viewed from above.

The art around the airport is also some people's cause for concern. Most notably, there is a 32-foot sculpture of a horse that fell on its sculptor and killed him. Murals around the airport are also troubling to some, including images of a Nazi officer in a gas mask, children near a burning building, and the devil jumping out of a suitcase.

There's a giant active volcano under Yellowstone in Wyoming, and if it erupts, it could wipe out the US. Conspiracists believe the government knows when the eruption will happen.

Yellowstone National Park is 3,500 square miles of wilderness, wild animals, and gorgeous landscapes. But under the park is something far more sinister. There is an active volcano that measures 44 miles across, and if it erupts, it could wipe out the entire US.

The volcano last erupted 630,000 years ago, but there are some conspiracists who are convinced the next eruption could happen any day. Some believe the US is drawing up contingency plans because the government knows the eruption is imminent. Conspiracists also point to videos of animals running from Yellowstone, which people think is a sign of the coming eruption. Experts say the animals are just running from tourists.

Some believe the chamber behind Mount Rushmore holds some big secrets.

Most people know Mount Rushmore as one of the most recognizable landmarks in the US as the faces of George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt are carved into it.

But not many people know there is a hidden chamber behind Lincoln's head. The sculptor Gutzon Borglum created an 18-foot door behind the landmark that leads to an open room that is 74 feet long and 35 feet high. Borglum intended to place America's prized possessions in this room. It was supposed to be called the Hall of Records.

While the room does contain important historical documents like the US Constitution and the Declaration of Independence, it is now sealed off from the public, leading many to create theories. Some believe the government is hiding something incredibly secretive there, like proof of extraterrestrial beings. Others believe there are hidden treasures in the room, an idea explored in Nicholas Cage's "National Treasure: Book of Secrets."

The Georgia Guidestones is a famous monument that is known for its bizarre inscriptions, which led to a number of conspiracy theories.

In 1980, a monument was built in Elberton, Georgia, and is known as the Georgia Guidestones. There are 10 guidelines on the monument written in eight languages, which seem to be a set of rules for humans. For instance, one inscription reads, "Maintain humanity under 500,000,000 in perpetual balance with nature," while another reads, "Rule passion — faith — tradition — and all things with tempered reason."

The monument was paid for by a man who gave an alias, so no one knows who built it or why. Some think the inscriptions are telling the future and giving us a guideline for how to rebuild after an apocalypse. Others believe satanists or the New World Order (a secret, world-controlling group) built the sculpture to promote their agenda.

In 1968, the Kentucky Derby was shrouded in conspiracy theories after the winner was stripped of his title.

In May 1968, Peter Fuller and his horse, Dancer's Image, won the Kentucky Derby and were given the $5,000 trophy. But three days later Fuller and Dancer's Image were stripped of their title because traces of phenylbutazone were found in the horse's bloodstream. People believed they cheated. Fuller was shocked and categorically denied the results, eventually taking the problem to court.

The situation rocked the Derby community, leading to many conspiracy theories. Since Fuller was an outspoken supporter of Martin Luther King Jr. and even gave money to his wife, Coretta King, some think anti-civil-rights believers sabotaged the horse. According to the Lexington Herald-Leader, others say it was an FBI plot orchestrated by J. Edgar Hoover because he disliked King and always tried to discredit the Civil Right Movement. All of these theories remain unproven.

Some people in Idaho say the government is poisoning them with chemicals.

Some people in Idaho believe the state is subject to government experimentation. They believe the government is dropping chemicals from airplanes at various times throughout the year. As evidence, they point to "chemtrails," or streaks in the sky that are supposedly left over chemicals. One man on YouTube recorded video of lengthy streaks in the sky in Idaho as evidence, while another pointed to the fact that he could no longer see the mountainous landscape because of chemicals in the air.

In 2015, 2,000 geese "fell from the sky" and were found dead in Idaho. While some believed it was because of the chemtrails, environmentalists said it was most likely because of an infectious disease known as avian cholera.

John Dillinger is Indiana's most notorious criminal, and a lot of conspiracies surround his jail escapes and death.

During the 1930s, Indiana-born John Dillinger became a national sensation and was named public enemy No. 1. He was wanted for the armed robbery of over 10 banks throughout Indiana and for stealing over $300,000. When he was arrested, he escaped prison by carving a gun out of wood and tricking the guards into letting him go. He then had facial surgery to become unrecognizable.

He was killed in an alley in 1934 after the FBI put out a $100,000 reward for him. This is where the conspiracy theories begin. Some believe Dillinger was not killed in the alley because of rumors that said the body had brown eyes while Dillinger famously had gray eyes. The body also had signs of illnesses the famous robber was never known to have. In 1963, The Indianapolis Star received a letter from someone claiming to be Dillinger, leaving many to believe that the criminal survived throughout the 1900s.

A sinkhole opened up in Louisiana, sparking conspiracy theories throughout the state.

In 2012, a 34-acre sinkhole opened up in Bayou Corne, Louisiana, and it's still growing. The New York Times described the incident as the day "the earth opened up — a voracious maw 325 feet across and hundreds of feet deep, swallowing 100-foot trees, guzzling water from adjacent swamps and belching methane from a thousand feet or more beneath the surface." Some even said they "caught a glimpse of hell in it."

But others believe this sinkhole is connected to the entire Gulf of Mexico, hinting at a future cataclysmic event that will swallow the entire region. In other words, everything between Texas and Florida will be sucked into the earth. There is no scientific proof that this is true.

When people could not find the body of Maine's sixth governor, Enoch Lincoln, conspirators theorized about its whereabouts.

Enoch Lincoln was a famous poet and early advocate for black and women's rights in New England. In 1826, he was elected Maine's sixth governor and during his term, he chose the current site of Maine's capital. When he died in 1829, his body was placed in a crypt. In 1991, an inspection of the crypt found no remains. Lincoln's body was missing, and this sparked a slew of conspiracy theories.

Some say state workers might have cleaned the tomb and just forgot to put the body back, while others theorize the governor was never buried there at all. His body has never been found.

By 1988, there were 3,000 reports of UFO sightings in Wytheville, Virginia.

In October 1987, Wythe County Sheriff Wayne Pike reported that he and his deputies witnessed strange lights in the sky. It sparked a full panic in Wytheville, Virginia, prompting many conspiracy theories. By 1988, there were 3,000 reports of UFO sightings in the area.

Jimmy Hoffa, a famous labor leader, disappeared in Michigan in 1975, sparking countless conspiracy theories.

Jimmy Hoffa made a name for himself as a compassionate and driven labor leader who devoted his life to advocating for worker's rights. He started his career in Detroit, working his way up through the International Brotherhood of Teamsters, a powerful union at the time. Eventually, he became the president of the union. Secretly, however, he was making deals with the local mob and was caught. When he was released from jail, he disappeared from a restaurant in Detroit.

Many believed he was the victim of a Mafia hit, but a body was ever found. Others are convinced the Teamsters murdered him so that he wouldn't become president again. It took seven years before Hoffa was officially declared dead, which sparked even more theories about where his body was. Some believe his body is buried beneath Giants Stadium, in New Jersey, while others believe he is buried under a swimming pool in Hampton, Illinois.

For years, people across Minnesota have reported hearing low humming or roaring sounds coming from the sky.

For years, cities across Minnesota have reported hearing bizarre humming sounds that seem to be coming from the sky. In 2011, for example, many people in Alexandria, Minnesota, caught the alarming sounds on camera, bringing attention to the phenomenon and sparking conspiracies. In 2018, the theories were reignited when another higher pitch sound was heard in Minneapolis.

Some simply blame it on airplanes, but others think the sounds are far more sinister. They believe the sounds are from extraterrestrial beings or secretive military training.

Some people believe the Joplin tornado in 2011 was actually created by the military.

On May 22, 2011, at 5:41 p.m., Joplin, Missouri, was hit with a devastating tornado with winds reaching 200 mph. The tornado leveled the town and killed 161 people. However, the out-of-this-world strength of the tornado led some to create conspiracy theories.

The most popular theory is that the tornado was created by the US military at a facility up in Alaska known as the High-Frequency Active Auroral Research Program (HAARP). The facility studies the earth's upper atmosphere but many believe it can create hurricanes and tornadoes, like the one in Joplin. Experts say this theory is false, according to ABC News.

Conspiracy theories surround a strange formation in New Hampshire known as Mystery Hill.

In Salem, New Hampshire, there is a 4,000-year-old archaeological site that no one knows how or why it was built. The site comprises chambers, walls, drains, and basins all made out of stone.

Some theorize that the rock formation was built by Native Americans in the region or by colonial settlers. When William Goodwin purchased the formations, he came up with the theory that the place was built by Vikings or Irish monks long before Christopher Columbus arrived in the Americas. Some even think the site dates to the medieval ages.

Another growing theory is that the site was used as a stop along the underground railroad to hide former slaves.

An abandoned ghost town in New Jersey became one of the internet's earliest conspiracy theories when people theorized the town was the site of a group that practiced interdimensional travel.

Ong's Hat is an abandoned town in the Pine Barrens of New Jersey. The town dates from the 17th and 18th centuries, but the population dwindled dramatically in the 20th century, ultimately making it a ghost town. Some believe the town became populated again a few decades later.

In the 1980s, a pamphlet was published saying Ong's Hat was home to a group of people that practiced interdimensional travel. The pamphlet claimed that the group started when two scientists from Princeton University moved into the abandoned town and eventually made "The Egg," which allowed people to travel to alternate universes. According to the pamphlet, the machine transported the entire group to a different dimension to escape police investigation. The theory spread throughout the internet.

Although some people have come forward to claim that they were part of this group at Ong's Hat, there is no evidence that this group existed.

People have witnessed mysterious lights floating around Brown Mountain in North Carolina, leading to a number of conspiracy theories.

September 24, 1913, marks the day the first time anyone had seen the Brown Mountain lights in North Carolina. In a Charlotte Observer article, a ball of light is described as floating through the valley and then disappearing.

"All theories as to its origin or nature have either been exploded or fall through from lack of evidence to support them,"the article reads. 

The lights became a conspiracy themselves, as people debated about their existence. But in 2016, a group of scientists appeared to capture the lights on camera.

"It was something out there. It came on and went back off virtually instantly four times over several minutes," one of the scientists told ABC. "We've eliminated all the things that are likely man-made natural sources, so we're left with no real explanation other than it's whatever the lights might actually be."

Theories as to what the lights are include ball lightning and natural gases.

The Safeguard Complex in North Dakota was built during the Cold War but some think it's related to the Illuminati.

The Stanley R. Mickelsen Safeguard Complex in North Dakota was built in the 1970s to detect incoming missiles. The $500 million building is shaped like an unfinished pyramid, much like the one you can see on the back of the dollar, and has a round circle on each face.

Mysteriously, the building was opened and in operation for only one day. It opened on October 1, 1975, and closed on October 2, 1975, when Congress decided to end the program, leading many to construct conspiracy theories. Some assume the building is actually used by the Illuminati because of its pyramid shape, which is a symbol of Freemasonry, the teachings of the largest secret society.

An astronomer at the Ohio State University recorded a signal that is theorized to be sent from an extraterrestrial being.

On August 15, 1977, astronomer Jerry Ehman recorded a radio signal using the Big Ear telescope at the Ohio State University. The sound was loud and lasted 72 seconds. Ehman wrote "Wow!" on the printout, giving it the name "The Wow! Signal." Unfortunately, the signal was never heard again, leading many to believe it might have been extraterrestrial.

Others theorize it was just a comet that the telescope was picking up, but Ehman doesn't think that is true. Some think the signal recorded was just a glitch in the telescope, according to Live Science.

The Masons hold an annual meeting in the Malheur Cave in Oregon, sparking conspiracies theories.

The Malheur Cave has a long and interesting history, dating from the precolonial era. The 3,000-foot cave was once used by Native Americans but is now owned by a Freemason group called Robert Burns Masonic Lodge. Every year, they hold a meeting inside the cave, raising a number of conspiracy theories.

Some conspirators are convinced the cave has a door to hell, while others think it connects to an underground tunnel system that stretches across the US to other Mason-focused locations. Others believe satanic worship and sacrifices occur in the cave.

Centralia, Pennsylvania, is famous for its fires that are burning underground indefinitely, making the town a ghost town. But some think the fire was government made.

In 1962, the town of Centralia lit a landfill on fire to get rid of its trash, but the fire spread throughout the coal mines that laid under the town. Eventually, the fires made the town unsafe, forcing people to move away. The fire still burns today.

Some believe there's more to the story. There are people who think the government started the fire to force people out of the town so it could collect billions of dollars worth of coal. According to local Pennsylvania news site PennLive, however, whatever coal might still be down there is worth far less.

In 2015, Rhode Island beachgoers experienced an inexplicable blast that some conspirators find suspicious.

In July 2015, a bizarre blast on Salty Brine beach in Narragansett knocked people off their beach chairs, injuring one person. Witnesses said they heard rumbling in the ground before the blast.

"There was a massive bang and I seen the actual rocks shift and move," one witness told CBS Affiliate WPRI. "And I started screaming, 'Get up, get up!' The same time I'm screaming, the sand erupted, threw my sister from there, like a live canon, face-down, unconscious 10 feet away."

Some conspirators believe there might have been explosives hidden in the sand, but there is no debris that would hint at that. Dan Bidondi of "Infowars" attempted to perpetuate the theory that the beach was unsafe because of explosives while interviewing beachgoers in Rhode Island on his YouTube channel.

According to the Providence Journal, Hydrogen from corrosion of copper cable likely caused the Salty Brine blast.

Mysterious clouds formed over Myrtle Beach, South Carolina, in 2011, prompting conspiracy theories.

On January 7, 2011, strange clouds appeared over Myrtle Beach, South Carolina. They looked as if they were a hole punched in the sky.

Utah's Skinwalker Ranch is a hotbed for conspiracy theories, especially UFO sightings.

In the 1990s, the Sherman family came forward and spoke to media outlets about years of strange occurrences at their ranch in Ballard, Utah. Terry Sherman told the press that his family had witnessed UFOs and strange lights. He also said his cows kept completely disappearing and then turning up mutilated. More bizarrely, Sherman said circular doorways would appear out of thin air. There were also reports of crop circles in the pasture. The farm quickly became famous across the US, eventually becoming known as the Skinwalker Ranch.

Over the years, more conspiracies arose about the Skinwalker Ranch, including a werewolf sighting. More strangely, reports of bizarre sightings date back long before the Sherman family. A newspaper from the '70s reported multiple witnesses in the area seeing a UFO surrounded by green light.

The Brunswick Springs in Vermont is so mysterious that there are theories about its powers.

The Brunswick Springs in Vermont has a long history surrounded by conspiracy theories. In fact, "Ripley's Believe It or Not" named the springs the eighth wonder of the world because there are six springs that each have completely different minerals despite coming from the same source. The minerals include iron, calcium, magnesium, sulfur, bromide, and arsenic.

The Abenaki Native Americans in the 1700s theorized that the springs had the power to heal illnesses. According to legend, when a soldier from the French and Indian War tried to bottle the spring, the natives cursed them.

Since then, four hotels were built throughout the years near the springs and each has mysteriously burned down. Conspiracy theorists believe it's because of the curse.

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