'Floating city' appears in clouds over China
A "floating city" has been seen in the skies above China, but experts say it is nothing but a optical illusion.
Thousands of people witnessed what looked like skyscrapers popping out from gathered clouds in two separate sightings.
The first appeared over Foshan in the Guangdong province of China.
A few days later, another cloud city appeared over the Chinese city of Jiangxi.
Many believed this was a window to a parallel universe, but weather experts said it was a known type of optical illusion.
"Fata Morgana" is a type of mirage that distorts objects in the distance, and can be seen at land and sea, The Daily Mail reported.
It is caused by light bending through various layers of temperature as it makes its way from the sun to the earth.
Our brain assumes that the light is travelling in a straight path. When it bends, our mind sees it as if it were straight - causing objects to shift into where our brain thinks they should be.
Despite this explanation, conspiracy theorists have been found a lot to latch onto with the floating cities.
YouTube channel Paranormal Crucible speculated that the apparition could be "the result of a project blue beam test".
The "Project Blue Beam" theory contends that Nasa are planning a faked alien invasion of earth or second coming of Christ through holograms.
The theory was born in the 1980s, but remains relevant to this day.