Satellite images taken by Google Earth have unveiled a mystery construction complex in the middle of the Chinese desert.
Former CIA analyst Allen Thomson was looking for an orbital tracking site near the city of Kashgar in southwestern China, when the strange lines and buildings caught his eye.
What appears to be a collection of structures and roads have baffled the expert who has been left puzzling what they might be.
‘I haven’t the faintest clue what it might be,’ he told Wired magazine.
‘But it’s extensive, the structures are pretty big and funny-looking, and it went up in what I’d call an incredible hurry.’
Mr Thompson, who left the CIA in 1985, has discovered similarly strange things on Google Earth before, such as the giant jigsaw grids in China in 2011 which appeared to be satellite calibrator grids.
But this time he has been left with no clue as to what it may be.
It is not the first time strange patterns and buildings have been uncovered in remote parts of China using Google Earth.
In 2011 patterns were discovered in the Gobi desert in China's north-east interior which remain unexplained.
However, this did not stop people from guessing, taking to online forums to establish their origins.
Some claimed that they were 'codes' designed to be read by UFOs, to fears that they were missile practice targets modelled on U.S. cities, before researchers came to the slightly less scary conclusion that some, at least, were used to calibrate cameras in China's spy satellites.
Late the same year, also in the Gobi, buildings and ‘masonic-looking’ road structures led to a number of more or less serious theories as to what the secretive superpower might be up to including nuclear bomb-making, Jetplane test range and driving schools.