In May 2011, reporters swarmed now-President Donald Trump as he exited the Hyatt in Washington, DC, after the White House Correspondents' Dinner.
Many wanted a response from Trump, who had just watched President Obama deliver jokes that night about Trump's constant questioning of the legitimacy of Obama's birth certificate.
Years later, Trump is still not convinced of the legitimacy of Obama's birth certificate. But this was perhaps the first of numerous debunked or unverified conspiracy theories that Trump has entertained during his time in the political spotlight.
Throughout the 2016 campaign and while in the White House, Trump has floated theories fueled by the conspiratorial-minded corners of supermarket tabloids and the internet, something unprecedented in modern politics. He's often used them as weapons against his opponents.
Here are some of the most notable conspiracy theories Trump has entertained:
Conspiracy theories Trump has entertained over the years
Conspiracy theories Trump has entertained over the years
Questions about Ted Cruz's father's potential ties to President John F. Kennedy's assassin.
On the eve of the Indiana primary, Trump attempted to undermine former Republican presidential rival Ted Cruz's father's legitimacy by parroting an unverified National Enquirer story.
It claimed Rafael Cruz was photographed in the early 1960s handing out pro-Fidel Castro leaflets with President John F. Kennedy's assassin, Lee Harvey Oswald.
The Cruz campaign denounced the piece as "garbage."
(Photo By Tom Williams/CQ Roll Call)
Questions about President Obama's birth certificate.
While mulling a potential 2012 presidential bid, Trump became the most high-profile figure to promote the rumors suggesting that President Obama was not born in the US.
Trump claimed he'd deployed private investigators who "could not believe what they're finding" about Obama's place of birth.
He also repeatedly clashed with reporters who pushed him on the issue. During one contentious interview, he told ABC's George Stephanopoulos that he'd been "co-opted" by "Obama and his minions" when the anchor tried to push back on Trump's claims.
"He had intimate knowledge of what was going on," Trump said of Foster's role in the White House. "He knew everything that was going on, and then all of a sudden he committed suicide."
He added: "I don't bring [Foster's death] up because I don't know enough to really discuss it. I will say there are people who continue to bring it up because they think it was absolutely a murder. I don't do that because I don't think it's fair."
(Photo credit should read BOB OCHEN/AFP/Getty Images)
Questions about whether Syrian refugees are ISIS terrorists.
Trump has, in part, justified his plan to temporarily bar Muslim immigrants from entering the US by claiming that refugees coming from Syria "could be a Trojan horse."
"It could be one of the greatest coups of all time," Trump told Fox News' Sean Hannity last year. "They could be ISIS. It could be a plot. I mean, I don't want to think in terms of conspiracy, but it could be a plot."
But the process for vetting refugees typically lasts 18 to 24 months, and immigration experts maintain it is one of the most difficult ways for terrorists to attempt to enter the US legally.
"It is extremely unlikely that someone who is a terrorist will be sent through the refugee resettlement program," Greg Chen, the director of advocacy at the American Immigration Lawyers Association, told Business Insider.
He added: "It takes a great deal of time, and it wouldn't make sense for someone who is a terrorist for someone to go through that process. There are going to be easier ways for a terrorist to try to infiltrate, rather than going through the refugee resettlement program."
(Photo by Andrew Harrer/Bloomberg via Getty Images)
Questions about whether an ISIS-linked terrorist attempted to charge at Trump on stage.
After an attendee at Trump's March 2016 rally in Dayton, Ohio, attempted to charge the stage, Trump claimed a video he retweeted proved the attendee was a terrorist linked to ISIS.
"He was playing Arabic music. He was dragging the flag along the ground, and he had internet chatter with ISIS and about ISIS. So I don't know if he was or not," Trump said. "But all we did was put out what he had on his internet. He's dragging the flag, the American flag, which I respect obviously more than you."
He added: "What do I know about it? All I know is what's on the internet. And I don't like to see a man dragging the American flag along the ground in a mocking fashion."
Asked about the circumstances of Scalia's death, Trump said he was unsure about what caused Scalia's death. Trump noted a pillow was found over the justice's face, a claim authorities rebutted.
"I'm hearing it's a big topic," Trump said in a radio interview. "It's a horrible topic but they're saying they found the pillow on his face, which is a pretty unusual place to find a pillow."
He added: "I can't give you an answer. It's just starting to come out now."
(Photo credit should read JEWEL SAMAD/AFP/Getty Images)
Questions about whether childhood vaccines cause autism.
At a Republican presidential debate in 2016, CNN host Jake Tapper asked Trump about his position that vaccines can cause autism.
"We had so many instances, people that work for me, just the other day, 2 years old, a beautiful child, went to have the vaccine and came back and a week later got a tremendous fever, got very, very sick, now is autistic," Trump said.
Shortly after Trump's assertion, former presidential candidate and neurosurgeon Ben Carson corrected the real-estate mogul, pointing out that overwhelming medical evidence suggests that there's no link between autism and vaccines.
A 2013 study from the Centers for Disease Control and Prevention found no connection between vaccines and an increased risk of autism.
(Photo by Ty Wright/Getty Images)
Questions about whether Muslims in New Jersey were cheering after 9/11.
For weeks last year, Trump emphatically claimed he saw televised news reports of Muslims cheering in New Jersey after the September 11, 2001, terrorist attacks.
"There were people that were cheering on the other side of New Jersey, where you have large Arab populations. They were cheering as the World Trade Center came down," Trump said during an ABC interview.
He added: "I know it might be not politically correct for you to talk about it, but there were people cheering as that building came down — as those buildings came down. And that tells you something. It was well-covered at the time."
Questions about whether wives of 9/11 hijackers fled to Saudi Arabia before the attacks.
The presumptive Republican presidential nominee repeatedly stated last year that the terrorists who carried out the September 11, 2001, attacks moved their families out of the US to Saudi Arabia several days before the hijacking.
"When you had the World Trade Center go, people were put into planes that were friends, family, girlfriends, and they were put into planes and they were sent back, for the most part, to Saudi Arabia," Trump said. "They knew what was going on. They went home and they wanted to watch their boyfriends on television."
The 9/11 commission report, the most extensive investigation into the events surrounding the attacks, determined that few of the hijackers kept in contact with their families, and none had family members living in the US.
Though many Republican leaders remain skeptical of climate change, Trump has taken his skepticism a step further. In 2012 he suggested that climate change is a "total, and very expensive hoax" perpetuated by China's government.
"The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive," Trump tweeted in 2012.
Trump backed off the tweet, telling Fox News in January that his comment was a "joke." Still, the real-estate mogul has repeatedly maintained that climate change was a hoax, and said climate-change studies are "done for the benefit of China."
According to NASA, 97% of publishing climate scientists believe that human activities such as burning of fossil fuels have caused climate change.
(Photo credit FREDERIC J. BROWN/AFP/Getty Images)
Questions about whether asbestos is a "great con."
When confronted on ABC's "This Week" about whether he believed Rubio was not constitutionally permitted to occupy the presidency, Trump, whose mother was born in Scotland, refused to disavow the tweet.
"I've never looked at it, George," Trump said of the tweet. "I honestly have never looked at it. As somebody said, he's not. And I retweeted it. I have 14 million people between Twitter and Facebook and Instagram, and I retweet things and we start dialogue and it's very interesting."
He added: "I'm not sure. Let people make their own determination."
(Photo by Chip Somodevilla/Getty Images)
Questions about Fox News being owned by a Saudi billionaire.
Trump's war with Fox News' Megyn Kelly recently reached a detente.
But during the peak of Trump's rhetorical battle with Kelly, he perpetuated a prominent outlandish theory from one of his Twitter followers.
In January, the real-estate mogul retweeted a photo purportedly showing Saudi billionaire Prince Alwaleed bin Talal with Kelly. The photo claimed the prince was a partial Fox News owner, which multiple outlets found was untrue. Alwaleed's investment company owns a small share of 21st Century Fox.
(Photo via Donald Trump/Twitter)
Questions about the legitimacy of the "Access Hollywood" tape
Toward the tail end of his presidential campaign, the 2005 "Access Hollywood" tape featuring Trump apparently admitting that he likes to grab women "by the p----" received broad coverage, and Trump apologized for his comments shortly afterward.
More recently though, after various allegations of sexual harassment in media and politics have begun to surface, Trump has walked back these comments.
"We don't think that was my voice," Trump reportedly told a senator, according to The New York Tiimes.
The Times' sources did not elaborate on why Trump has begun to doubt the authenticity of the tape's audio.
(Photo via NBC)
Claims that Joe Scarborough killed one of his interns
In a tweet Trump sent Wednesday morning, he made references to a conspiracy theorythat claims MSNBC anchor Joe Scarborough of "Morning Joe" murdered one of his staffers in Florida in 2001.
"So now that Matt Lauer is gone when will the Fake News practitioners at NBC be terminating the contract of Phil Griffin?" the tweet read. "And will they terminate low ratings Joe Scarborough based on the 'unsolved mystery' that took place in Florida years ago? Investigate!"
While Scarborough was serving as a Republican congressman in Florida's 1st district, one of his interns, Lori Klausutis, was found dead in the office. A coroner found no evidence of foul play, and indicated that the death occurred because of a heart problem that caused the intern to fatally hit her head on her desk.
(Photo by Shannon Finney/WireImage)
Claims that Obama had wiretapped Trump's phone
In March 2017, Trump sent a tweet accusing Obama of wiretapping his phones in Trump Tower.
"Terrible!" Trump wrote, "Just found out that Obama had my 'wires tapped' in Trump Tower just before the victory. Nothing found. This is McCarthyism!"
PolitiFact and other outlets have debunked the claim. An Obama spokesman also issued a response to the allegation, saying: "Neither Barack Obama nor any White House official under Obama ever ordered surveillance of any U.S. citizen."
(Photo credit should read BRENDAN SMIALOWSKI/AFP/Getty Images)
Claims that voter fraud in the 2016 election cost him the popular vote
In a tweet sent shortly after the November 2016 election, Trump wrote: "In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally."
This unsubstantiated claim was repeated by Kris Kobach, the chairman of Trump's panel on voter fraud, in July. The fact-checking site Snopes has debunked the claim entirely, citing "zero evidence."
(Xinhua/Wang Ying via Getty Images)
Retweeting anti-Muslim conspiracy videos
In November 2017, Trump caused diplomatic havoc by retweeting three videos posted by Jayda Fransen of the ultra-nationalist, anti-Muslim organization Britain First that purportedly showed Muslims in Europe committing crimes and destroying Christian icons.
Britain First has frequently targeted mosques and Muslims in the UK in order to brand all Muslims as violent extremists, and Trump's retweet of the videos was widely seen as a tacit endorsement of the group's efforts.
Although the authenticity of the videos has been called into question, White House press secretary Sarah Huckabee Sanders has maintained this doesn't matter.
"Whether it's a real video, the threat is real," she told reporters.
(Photo by Omar Marques/SOPA Images/LightRocket via Getty Images)
Claims 3,000 people didn't die in Puerto Rico after Hurricane Maria and that Democrats inflated the death toll.
In a tweet on Thursday morning, Trump claimed 3,000 people didn't die in Puerto Rico after Hurricane Maria and accused Democrats of inflating the death toll to make him "look as bad as possible," rejecting the findings of a government-funded study in the process.
"3000 people did not die in the two hurricanes that hit Puerto Rico," he said. "When I left the Island, AFTER the storm had hit, they had anywhere from 6 to 18 deaths. As time went by it did not go up by much. Then, a long time later, they started to report really large numbers, like 3000…"
He then added: "This was done by the Democrats in order to make me look as bad as possible when I was successfully raising Billions of Dollars to help rebuild Puerto Rico. If a person died for any reason, like old age, just add them onto the list. Bad politics. I love Puerto Rico!"