Mysterious black rings are appearing in the sky worldwide, igniting conspiracy theories they're related to aliens.
Most recently, 22-year-old Kimberley Robinson photographed a "smoke vortex" in the sky above a freeway in Yorkshire, England, on the weekend of July 8, the Daily Mail reports.
"Me and my boyfriend were driving today and noticed a black flying ring in the sky," Robinson said. "It looked a bit smokey but the shape was a solid ring."
It's just one of many like it spotted in the past few years.
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A similar ring was spotted above California's Disneyland in April 2016. Meanwhile, rings were also seen in 2014 in Kazakhstan and in 2015 in Warwick, England.
"Everyone watched it in fear/confusion," recalls Kyle Hawkins, who was at Disneyland when the ring appeared, reports The Huffington Post. "I half expected an alien portal to open up through this ring as we were gazing up in disbelief...The strangest thing I've ever seen."
Nigel Watson, author of "UFOs of the first World War," says this most recent sighting may not be so out of this world, after all.
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"Smoke rings in the sky like this one look very spooky and unusual," said Watson. "In this case it isn't an extraterrestrial spacecraft from planet Zog sent by evil aliens, but the byproduct of cannon fire of a battle reenactment at the nearby Yorkshire Wartime Event."
It is likely, then, that the smoke ring seen in 2014 in Warwick was also a byproduct of the pyrotechnics used at Warwick Castle.
Other experts also point out similar rings have been spotted at music festivals like Burning Man, further squashing notions of extra terrestrials.
"Despite exotic theories about UFOs, aliens, or portals to other dimensions, I believe there's a decidedly down-to-earth explanation here," said Nick Pope, who used to investigate UFOs for the UK's Ministry of Defence. "A so-called smoke vortex can arise when you have a blast through a circular structure like a smokestack. So these weird effects can be caused by accident -- or indeed by design."
However, some are not convinced by such. Some wondered how one could explain the other rings -- in Kazakhstan, for instance, or Disneyland.
"It was a windy night, couldn't have been a smoke ring," said Hawkins, recalling when he saw the ring at Disneyland.
Yet another individual -- who claims to have also seen the ring -- disagreed.
"I've personally seen this 'mysterious ring' form while visiting 'the Magic Castle at the popular theme park in California,'" wrote one Daily Mail reader. "They use a large pyrotechnic torch for one of their evening shows, and if the humidity is right it makes a smoke ring that slowly floats up ... and lingers for minutes."