A monument of light in the empty space of the two towers of the World Trade Center
There are people in many countries around the world who believe in 'conspiracy theories' - their idea: the way people know about the most widely circulated events, the fact that it did not happen - is something else. They also presented various facts and evidences in favor of this.
One of the recent events that has spread such conspiracy theories is the September 11, 2001 terrorist attacks in the United States.
On that day, extremist Islamist terrorists hijacked four passenger planes and hit two of them at the World Trade Center building in New York, one at the Pentagon in Washington, and another at a field in Pennsylvania. In all, about 3,000 people were killed.
There are various 'conspiracy theories' about that incident. For example: neither the US government nor the Israeli intelligence service was behind the attack, no Jews were killed in the attack, no planes actually hit the Twin Towers or the Pentagon - things like that. Another big theory is that the two towers of the World Trade Center collapsed, not because of a plane crash, but because of explosives planted inside the building.
Today, even after so many years, the discussion and debate on these theories is not over.
The first conspiracy theories spread within hours of the attack on the Twin Towers.
David Rustchek, an internet user, wrote, "Did anyone notice that the World Ted Center building was not destroyed by a plane? Or was it just me who understood it?"
That said, the two buildings were hit by planes and a lot of damage was done - but the way the two towers collapsed, the explosives had to be placed in the right places inside. Someone has to take a lot of time to do this. The question is: what was the purpose of the planes?
However, later investigations revealed that the structure of the two towers was weakened by the fire after the plane crashed and the entire building collapsed under its pressure as the upper floors collapsed.
But there are still some people who do not believe this.
That 9/11 attack caused a stir around the world
Something happened in New York
On September 11, Matt Campbell went on holiday to Lanzarote with his wife and children. His wife bought something from the store and came back and said, 'Something happened in New York.' Then they saw the news of the attack on TV.
Within hours, news came that Matt's brother, Jeff, was in the north tower at the time. Jeff has not been heard from since.
Jeff had been living in Manhattan, New York, a few years before. Worked at Reuters news agency. A conference was being held on the 108th floor of the North Tower, where he was present.
Matt was saying, we assumed the worst had happened.
They went to New York and searched various hospitals. There was no gain. They realized Jeff was dead.
Finally, part of his shoulder bone was found in the wreckage of the World Trade Center in 2002. However, the investigation of the incident was completed by 2013.
Three brothers Rob (left), Matt and Jeff
In the meantime, Matt's mind began to question the official response to the 9/11 attacks. However, he did not believe in a specific conspiracy theory, although there is no shortage of such theories online.
Matt is convinced that a lot of things have been covered up about exactly how his brother died, and he can't answer many questions.
"It started in October 2001. As the days went by, I saw an increasing number of inconsistencies."
Matt says he sought details of the incident from the FBI and other investigating agencies under the Right to Information Act. But they did not provide information for various reasons. "I have not yet received any preliminary evidence from them."
Jeff is not alone. More than half of Americans believe the government is withholding information about 9/11, according to a 2016 survey by Chapman University in California.
Some of the conspiracy theories circulating online are extremely dramatic.
The ruins of the Twin Towers
In some cases, the US government itself was involved. Some say U.S. officials deliberately allowed the attack to take place. Many others said the government was involved in planning the incident.
Experts say conspiracy theories have spread because people can't believe that only a handful of people can wreak such havoc with sophisticated weapons.
Karen Douglas, a professor at the University of Kent, says people want an explanation when something important happens. But often the official interpretation may not satisfy the people.
"They want the facts to be the same size - the explanation has to be the same. Conspiracy theories are born without that," said Professor Douglas.
On the other hand, these theories continue to be propagated in the online world - so they have not been erased from the minds of people in a decade and a half.
9/11 Memorial in New York
Professor Douglas said the information is shared on the Internet or through social media among people who share similar views.
Several books and films have been instrumental in propagating these conspiracy theories.
David Ray Griffin, a professor of philosophy and theology, wrote a book in 2004 called The New Pearl Harbor. He blamed the US government for the 9/11 attacks.
The first episode of director Dylan Avery's 'Loose Change' series aired in 2005. It ranks among the "popular" conspiracy theories surrounding the 9/11 attacks. Millions of people have seen these, shared them on the Internet. Even after Osama bin Laden was killed, a digital copy was found in his home.
In 2006, Richard Gage, a California architect, formed a group of architects and engineers called 'A Nine Eleven Truth' to reveal the truth about 9/11. They questioned the official details of the incident that day.
In addition to the two towers of the World Trade Center, another 48-storey building called WTC 100 meters away was also destroyed that day. But the plane did not hit the building.
However, a BBC report on the collapse of the building also created confusion and questions. Twenty minutes before the building actually collapsed, a BBC report said the building had collapsed.
However, a 2006 report from the American Institute of Standards and Technology stated that the building collapsed after a main pillar of the building collapsed in a fire.
However, this report did not please the conspiracy theorists.
Matt Campbell is still searching for the answer to his question.
He went to Guantanamo Bay to attend a pre-trial hearing of Khalid Sheikh Mohammed, the mastermind of the attack.
Matt Campbell called the hearing a "farce."
"But that's where I got the closest I could get to my brother's murder trial," he said.