Locals have been left perplexed after spotting what appears to be a hovering circle in the sky.
The odd phenomenon appeared above Yulin in the Shanbei region of Shaanxi Province, China, on 17 June and resembles a dark, smoky ring sitting mid-air.
Ever since it appeared, many have been looking for an explanation as to what it actually is.
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Experts looking into the strange occurrence believe it could be a ring of smoke or condensed water caused by combustion.
These types of smoke rings can often appear to hover in the air due to pressure changes in the atmosphere.
Another possible reason could be insects, which sometimes gather in huge numbers in order to reproduce.
Some think it could have also come from an explosion, or a firework display.
A similar dark ring was spotted in Leamington Spa in 2014, and it was actually found to have been caused by fireworks at Warwick Castle.
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Mr Qiao, who took a video of the rings over the Chinese city, said he hoped someone would be able to explain what the circle is and how it happened.
He said: "I looked up and saw this black circle rising into the sky very slowly. There were several of these smoke rings.
"I didn't know what they were, so I took a video of them. I am hoping somebody can explain it?"
A few years ago, security footage in the UK captured an eerie black ring floating in the sky.
The clip, which was shared on TikTok by user @farmmommalife, showed the ring hovering, almost motionless, with wisps of smoke emanating from within.
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Many people commented to ask what was going on, with some left wondering whether it was 'a portal to another dimension' or even 'a portal from all the anime worlds coming to Earth'.
After one appeared in the UK near Birkenshaw on the M62 a few years back, a UFO investigator ruled out any chance of extra-terrestrial action.
Nick Pope, who investigated UFOs and other mysteries for the Ministry of Defence in the past, explained at the time: "Despite exotic theories about UFOs, aliens, or portals to other dimensions, I believe there's a decidedly down-to-earth explanation here.
"A so-called smoke vortex can arise when you have a blast through a circular structure like a smokestack.
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"So these weird effects can be caused by accident - or indeed by design.
"On this latter point, they can be created as a sort of pyrotechnic effect, and it would be interesting to know if there were any outdoor festivals being held in the area concerned.
"I realise that by debunking this I'll probably be accused of working for the Illuminati or something, but I genuinely think we can close the case file on this one."
Topics: Environment, World News, China, Weird
Lucy Devine