The footage which was recorded by a local resident appears to show a huge mysterious city, including skyscrapers, floating in the clouds over the city of Foshan in in central Guangdong province, China on October 7, 2015.
The apparition which was witnessed by hundreds of shocked local residents only lasted a few minutes before completely disappearing.
One possibility, discussed on several forums, is mirage, a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Another possibility is a Fata Morgana, one kind of superior mirage.
However, others have the raised the fear that this mysterious phenomenon was possible the result of a project Blue Beam test, a holographic technology performed in order to test the reactions of the residents of the city Foshan or it was a temporarily vortex of a possible parallel universe.