400 mysterious ancient stone structures discovered in Saudi Arabian desert

The structures look like flat field gates from top in the images obtained from Google Earth

Scientists have discovered about 400 previously undocumented stone structures known as 'Gates' in Saudi Arabia with the help of Google Earth imagery.

While Saudi Arabia is largely thought of as barren mountains and desert, it was also home to an immense number of archaeological sites that were yet to be identified, recorded and mapped, said David Kennedy, researcher at University of Western Australia.

"You can not see them in any intelligible way at the ground level but once you get up a few hundred feet, or with a satellite even higher, they stand out beautifully," Kennedy said.

The structures look like flat field