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In July a tongue-in-cheek Facebook event was created to coordinate a raid on Area 51, the classified military base in Lincoln County, Nevada. It became an online sensation. Over 2 million Facebook users signed up, Jimmy Kimmel and Stephen Colbert gave it a spot on their respective talk shows, and the US Air Force strongly advised citizens against raiding the facility. But now, the Facebook event page has been taken down.

It appears as though Facebook took the page down on Aug. 3 for violating community standards. Mathew Roberts, the event creator, posted a screenshot on his personal Facebook page of the notice Facebook had sent him saying it had taken down the event because it "went against" Facebook's "Community Standards."

"I never got any reason behind the event being removed," Roberts told CNET. "I created a sister event which amassed about 15,000 people before being taken down for no reason."

After starting the Facebook event as a joke, Roberts is now planning an actual Area 51 festival in Nevada to take place Sept. 20, the day the facetious raid was to go down. He says he created another Facebook event, this time for the real festival that would take place somewhere that's not a highly-classified military base, but this too was taken down by the social network.

"I think it's pretty reckless of Facebook, especially because I'm trying to direct people away from storming the base," Roberts said. "And now I've lost my entire audience." Roberts expects around 20,000 people to attend the festival.

Facebook has been contacted for comment.

The now-deleted Facebook event came with a brief description: "We will all meet up at the Area 51 Alien Center tourist attraction and coordinate our entry," it read. "If we Naruto run, we can move faster than their bullets. Let's see them aliens."

"Naruto run" refers to the main character in the eponymous Naruto anime.

The Facebook event created the Area 51 meme, which became a fixture on Twitter and Reddit throughout July. You can see some of our favourites below.

My motivation to study Vs. My motivation to get into Area 51 pic.twitter.com/lF7TbFb5RU — College Student (@FactsOfSchool) July 13, 2019

Area 51 is a highly classified zone around 150 miles from Las Vegas, Nevada, a detachment of the famed Edwards Air Force Base. No one really knows what the base is used for, but it's speculated to be a location for aircraft development, and as such Area 51 has become synonymous with alien conspiracies. The most popular involve alien spaceships or aliens themselves, all allegedly kept within the classified zone.

The location reportedly received its name when, in 1951, the remains of the alleged Roswell UFO (said to have crashed in 1947) were brought to the base. In 2013, the CIA issued a 355-page declassified report detailing the birth of Area 51 and the U-2 spy planes developed and tested there.

Originally published Aug. 5, 7:30 p.m. PT.

Update, 9:38 p.m.: Adds comment from event creator Mathew Roberts.