Video Produced by Gaby Levesque

RACHEL, Nev. — They started arriving in the middle of the night.

Not the aliens. The RVs, packed with UFO enthusiasts, conspiracy theorists and those just looking to party in a remote area of the Nevada desert for “Storm Area 51,” a gathering that began as an internet joke but is expected to attract several thousand people here over the next three days.

“Look around. It’s happening. It’s here,” said Connie West, co-owner of the Little A’Le’Inn, which is hosting one of two competing “Alienstock” events this weekend.

The original “Storm Area 51, They Can’t Stop All of Us’” Facebook post was supposed to be a joke inspired by a recent documentary on the once secret military research site known as Area 51, part of the Nevada Test and Training Range, where conspiracy theorists allege the U.S. government is engaged in extraterrestrial research.

More than 2 million people on Facebook signed up.

Attendees of "Alienstock" speak to reporters in Rachel, Nev., ahead of this weekend's gathering of UFO enthusiasts. (Yahoo News)

[Photos: Earthlings descend on Area 51 for aliens, parties]

“We decided to come here because we saw the big meme,” said Alexandra Bousson, from West, Mich., fully dressed in an alien costume. “We thought, ‘Hey, wouldn’t it be fun if we went there?’”

And while the vast majority were likely in on the joke, the overwhelming response was taken seriously by local, state and military officials, who warned that “any attempt to access military installations or military training areas is dangerous.”

Last week, two 20-something Dutch nationals and YouTube filmmakers were arrested for trespassing at the Nevada National Security Site. According to police, the two had driven roughly 3 miles into the property at the time of their arrest.

Lincoln County Commissioner Varlin Higbee said more than 300 law enforcement personnel and first responders from across the state have been dispatched to handle any possible attempts to “storm” the gates.

“We’re prepared,” Higbee said.

Signs warn unwanted visitors not to trespass at the Nevada Test and Training Range. (Yahoo News)

[‘Storm Area 51’ is a joke, but the Pentagon takes plans seriously]

Story continues

Connie West, too, warned against any such attempt.

“It’s a dumbass idea,” she said. “Don’t let me catch you.”

Theories about the government covering up alien activity abounded after the 1947 crash of a high-altitude balloon in Roswell, N.M. (The government didn’t reveal until decades later that the crash was of an unmanned craft that was part of a top-secret program to monitor Soviet weapons tests.)

Rumors surrounding Area 51 date back to 1955, when President Dwight D. Eisenhower ordered the CIA to create the Groom Lake test facility. Originally it was used to test top-secret warcraft, like the U-2 spy plane. Since then, the base has been an operating, highly active and highly classified location that remains the center of UFO intrigue.

“I’ve been watching the sky for the last month or so — well, for the last 31 years,” said Pamela Kinsey, a waitress at Little A’Le’Inn. “Some stuff that I’ve seen that I never saw before that has gotten massive.”

___

Read more from Yahoo News: