Hundreds of mysterious structures have been uncovered by archaeologist in the desert lava fields in Saudi Arabia by using Google Earth.
David Kennedy of the University of Western Australia discovered around 400 previously undocumented stone walls that could be more than 9,000 years old in the western Harrat Khaybar region of the country.
As these structures resemble old-fashioned field gates, they have been called "gates" and though their purpose is unknown, these gates are known to the Bedouin as “Works of the Old Men”.
These structures vary greatly in size, from the longest measuring more than half a kilometre to the shortest in just 13 metres.
"The lava fields are often rich in archaeological remains, implying a moister past and more abundant vegetation, and recent fieldwork identifying larger settlement sites supports this notion", Kennedy wrote in his paper.
After from the new findings, other well-known structures at the sites are "kites", which archaeologists say were used for hunting.
The paper will be published in the upcoming issue of Arabian Archaeology and Epigraphy.