Some are saying it's a glimpse into a parallel universe. Others are speculating it's massive hologram produced by previously unknown Chinese technology displayed over a large populace to gauge its reaction.
But according to Mysterious Universe, others have a more down-to-earth explanation for the ghostly yet highly-detailed city that appeared in the clouds over Fosham, China, and again over Jiangxi. It also happened over Huansham City in 2011 with enough detail to reveal trees hovering in the sky.
Wired Magazine has described a phenomenon called a Fata Morgana, which has frightened and bewildered people throughout history. A Fata Morgana is a very complex mirage created by moisture in the air bending light and causing people's brains to interpret a repeated, offset image hovering above the true object. That's the very simple explanation, and it might describe the legend of the Flying Dutchman.
Or you could go with the conspiracy theorists who are claiming it's part of alleged New World Order program by NASA to fake the Second Coming of Christ.
What do you think?