UFO enthusiasts have descended on rural Nevada near the secret US military installation known as Area 51, long rumoured to house government secrets about alien life, with local authorities hoping the visitors were coming in peace.
Some residents of Rachel, a remote desert town of 50 people a short distance from the military base, worried their community might be overwhelmed by unruly crowds turning out in response to a recent, viral social-media invitation to "storm" Area 51.
The town, about 240km north of Las Vegas, lacks a grocery store or even a gasoline station.
Dozens of visitors began arriving outside Rachel's only business - an extraterrestrial-themed motel and restaurant called the Little A'Le'Inn - parking themselves in cars, tents and campers. A fire truck was stationed nearby.
One couple, Nicholas Bohen and Cayla McVey, both sporting UFO tattoos, travelled to Rachel from the Los Angeles suburb of Fullerton with enough food to last for a week of car-camping.
"I've always been into aliens because when I was born my uncle told me that my mom got abducted and turned me into a half-breed alien," joked Bohen.
"I was told that story my whole life and I have always been into aliens, into the whole scene and I have always wanted to come out to Area 51 to see the black mailbox and whatever else. And there is not a better time than now to do it. So, I got the time off and everybody said I was crazy but it seemed like a good idea to me," he added.
Area 51 was shrouded in secrecy for decades, stoking conspiracy theories that it housed the remnants of a flying saucer and the bodies of its alien crew from the crash of an unidentified flying object in Roswell, New Mexico, in 1947.
The US government did not confirm the base existed until 2013, when it released CIA archives saying the site was used to test top-secret spy planes.
The documents, however, did not end suspicion about space aliens there.
Rachel and its surroundings have long celebrated their place in UFO lore as a tourist draw.
A 158km road running through the area is dubbed the Extraterrestrial Highway, a purported hotbed of UFO sightings.
In June, California college student Matty Roberts posted a facetious Facebook invitation exhorting the public at large to run into Area 51 on foot to "see them aliens".
When more than one million people expressed interest, the US Air Force admonished curiosity seekers not to breach the gates at the military base, which it said is still used to test combat aircraft and train personnel.
Roberts then teamed up with Connie West, co-owner of the Little A'Le'Inn, to plan a music festival in Rachel dubbed "Alienstock" to entertain the expected crowds.
In early September, however, Roberts disassociated himself from the Rachel event, saying it was poorly organised and he feared it could devolve into a public safety crisis.
Instead, he helped stage an alternative Alienstock in Las Vegas. Beer brand Bud Light signed on as a sponsor and designed limited-edition, green beer cans featuring alien heads.
West said the event in Rachel would go on as planned.
"You know I can't anticipate or predict what is going to happen. But do I think there is going to be a disaster? No. Do I think somebody might get hurt? Of course. It doesn't matter what you do.
"My friend tripped last night and she trips over her own feet. But, you know, I think we have a really good handle on it because of the people that are here, the people from all over the world who have come here to volunteer," she said, adding that some visitors had come from as far away as Australia and New Zealand.
About 64km east of Rachel, the small town of Hiko planned an event called "Storm Area 51 Basecamp" at a gift shop dubbed the Alien Research Center.
Organisers promised musicians, artists and "prominent ufologists," and sold 3,200 tickets, according to the store manager.
The influx of alien hunters prompted Lincoln County, which encompasses Rachel and Hiko, to draft an emergency declaration that could be invoked if needed to call in help from the state.
The Lincoln County Sheriff's Office said visitors should expect "a large presence of law enforcement." Authorities urged everyone to bring ample supplies of food, water and fuel.
Despite a festive, peaceful mood back in town, the official Rachel website was decidedly unwelcoming.
"If any event still happens it is going to be a pretty sad affair with no bands, no food, very little infrastructure and a lot of unhappy campers," it said.