In a remote desert area in Saudi Arabia, archaeologists have found around 400 mysterious stone structures on the edge of volcanoes that are possibly thousands of years old.
The team found the stone structures using Google Earth and these formations have been dubbed the ‘gates’ because they appear to look like field gates from above, reported UK’s Mail Online.
Some of these strange features are more than four times the length of a football pitch, and are built on ancient lava domes and were found in the Harrat Khaybar region in Saudia Arabia.
These structures may be up to 7,000 years old, according to experts, but they have not been able to find out the purpose of these ‘gates’.
Some of the ‘gates’ go up the side of the lava dome.
The strange cluster appear to be the oldest man-made structures in the landscape and some are up to 1,700 feet long and built across old lava domes.
The smallest gates are 43 feet (13 metres) in length while the longest are 1,699 feet (518 metres) long.
Many of the structures have multiple stone walls that form a rectangular design whereas others - called ‘I’ type gates - have one stone wall with piles of stones at the ends.
Experts say that thousands of years ago this area would have been much more hospitable than it is now.
According to David Kennedy of the University of Western Australia, the purpose and age of these structures, remain unknown.
His paper on the subject due for publication next month in the journal Arabian Archaeology and Epigraphy, wherein he wrote: “Gates are found almost exclusively in bleak, inhospitable lava fields with scant water or vegetation, places seemingly amongst the most unwelcoming to our species.”
The gates are “stone-built, the walls roughly made and low”, he said.
Remains of lava flows can be seen on top of some of the gates, suggesting that they are older than some of the lava flows. The strange clusters “appear to be the oldest man-made structures in the landscape.”