In 2015, what seemed to be a floating city appeared in the clouds over Foshan in the Guangdong Province of China, sparking speculation of windows into parallel universes, aliens, mirages, and other phenomena.

Less than a year later, it appeared again, this time in China’s Liaoning Province in March of last year, adding to the discussion. Since this last appearance in 2016 , the debate over just what this “cloud city” is has died down, until recently, when the  baffling phenomenon appeared yet again in Yueyang, China.

Some argue that the images in the sky  are evidence of another universe leaking into ours, and what we are seeing are windows into this universe. Others claim that these ghostly appearances are evidence of UFOs, government holograms, and signs of the end of time.

Skeptics were quick to disprove these claims with arguments of their own. Some rational thinkers believe that these occurrences can be explained by natural means. A mirage known as the Fata Morgana is what most news sources say is the cause of the floating cities. According to Wired, a Fata Morgana is “light reflecting from a distant object such as a ship is bent downward as it passes through the colder, denser air near the surface of the ocean (or sometimes cold land, particularly ice). But your brain places the object where it would be if the light came to you in a straight path—higher than it actually is. This bending effect can even work with the curvature of the Earth if conditions are just right, which is why some fata morgana images can actually be refracted cities and ships from beyond the horizon. However,  a youtuber who has dedicated his career to debunking faked videos, images, and hoaxes, explained that this is impossible. The city in the sky does not share some characteristics that the Fata Morgana has. For example, the floating Chinese cities are far too high in the air to be mirages.

Another claim that has been disproven by the same youtuber, who goes by “Captain Disillusion,” is that the floating cities are just the top of skyscrapers in the distance whose lower parts are covered by smog. Captain Disillusion pointed out that there are no skyscrapers or urban buildings of that size in the areas around or near the appearances.

This new evidence in favor of the mystical explanation of the debate keeps the argument heated and running. What seemed to be an occurrence with a rational explanation has now become more complicated. New conspiracy theories and otherworldly explanations are sure to transpire from this new evidence.