Area 51, a military facility located in southern Nevada, is popularly known as the site of rumored government studies of outer space aliens. The "Storm Area 51" Facebook event, which started as a joke, went viral in July as people pledged to crash the secret military base in an attempt to "see them aliens." More than 2 million Facebook users have now said they are going, with over 1.4 million replying they were interested.
After going viral, the event spurred two rural Nevada counties to draft emergency declarations, with local law enforcement planning to team resources with the state and neighboring counties ahead of the Sept. 20-22 events.
The Arizona vacation destination is also apparently a well-known one for UFO sightings.
Lauren Hillhouse, GetYourGuide's Destination Manager for Arizona and Nevada, told Fox News on Monday of the area's "very interesting" opportunities, including night walks that give visitors the chance to look for UFOs.
The tour and attractions company offers guests night-vision goggles to explore unidentified flying objects in the night sky.
"A UFO guide will assist in tracking the nocturnal activity, which includes flashing lights, UFOs changing size rapidly, and winding in and out of the mountains around you," according to GetYourGuide.
Atacama Desert, Chile
The dark skies of Chile's Atacama Desert have helped the most arid place on the planet become a top spot for UFO-hunters.
"With one of the highest UFO sightings on record, Chile has become a favorite destination among UFO-seekers from around the world," according to GetYourGuide. "Thanks to low humidity, high altitude ridges and clear skies with little pollution, the Atacama Desert is the best destination for a sighting."
The company provides a two-hour astronomical tour that offers travelers two different views of the night sky.
The first part of the tour utilizes a telescope to observe the night sky, while the second part comprises "an ethnic astronomical journey to understand how the ancient inhabitants of the Andes interpreted the universe," according to GetYourGuide.
Stonehenge and Avebury, England
The medieval village of Avebury is ringed by the largest stone circle in the world, believed to be more than 2,000 years older than neighboring and popular Stonehenge.
Hillhouse told Fox News on Monday that tours of Stonehenge are "a big one" over the years.
The origins of Stonehenge have been widely debated. Earlier this year, a study suggested that the mysterious structure may have been built using pig fat.
In February 2019, a study suggested that prehistoric sailors may have been responsible for the legendary structure. In August 2018, a study found that 10 of the cremated remains buried at the prehistoric monument came from western Britain, with some from southwest Wales, as opposed to Wiltshire, where the monument was built.
GetYourGuide provides a full-day tour from London or Glastonbury that includes a walking tour of Avebury and a guide to lay out all the theories around Stonehenge's history.
Albuquerque, New Mexico
It may not have the alleged alien history of Roswell, but Albuquerque is also a big one for extra-terrestrial fans, according to Hillhouse.
One of the tours offered by GetYourGuide focuses on Hollywood blockbusters and television shows filmed in the area that Hillhouse described as for those "less interested in real aliens" and more for the cinematic kind.
"It's a nice sort of intimate tour in a minibus," she told Fox News.
Along the way, people can see the spot where dozens of films have been shot, including "Terminator," "Transformers" and "Independence Day 2."
Fox News' Chris Ciaccia contributed to this report.