Archaeologists Discover 4,000-Year-Old Wall Built Around Oasis in Saudi Arabia

Researchers have discovered a miles-long wall around an oasis in Saudi Arabia’s North Arabian Desert.

Built about 4,000 years ago, the fortification surrounds Khaybar, one of the area’s oldest oases—fertile, green regions of the arid desert. It likely helped defend against both nomadic raiders and natural threats.

The team measured the wall by comparing field surveys and remote sensing data with architectural studies, per a statement from France’s National Center for Scientific Research (CNRS). After performing radiocarbon dating on charcoal fragments found beneath and inside the wall, they concluded the structure was built between 2250 and 1950 B.C.E., according to a new study published in the Journal of Archaeological Science: Reports.

While the wall was originally 9 miles long, 16 feet tall and between 5.6 and 7.9 feet thick, deterioration over thousands of years shrunk it to 41 percent of its initial length. Just 74 of its original 180 bastions, or protrusions built into the walls, remain, as Live Science’s Owen Jarus reports.

In the third and fourth millennia B.C.E., many oases in the North Arabian Desert were inhabited by sedentary populations. The Khaybar Oasis wall enclosed more than 2,700 acres of land, according to Newsweek’s Aristos Georgiou. The researchers write that such walled oases were “a key component of the archaeological landscape and the sociopolitical evolution of northwestern Arabia through time.” Groups built the fortifications around natural water sources in the desert to protect and develop their own lush, agriculturally viable landscapes.

One likely motivation for building the Khaybar Oasis wall was for military defense “against raids from nomads,” lead author Guillaume Charloux, an archaeologist with CNRS, tells Live Science. The researchers write that mobile groups in the desert often attacked oasis settlements, and such assaults were “a well-known danger for sedentary populations during pre-Islamic and Islamic times.”

The people of Khaybar may have also built the wall to safeguard their land from natural erosion and destruction by flash floods. Another possibility is that they made it to “ostentatiously demarcate” their territory, exerting control of the landscape, write the researchers.

The wall exemplifies a shift away from nomadic life and towards permanent settlements in the region. As the researchers write, “The ramparts of Khaybar were probably built by Indigenous populations as they settled down.” The fortification would have taken four years to complete, using 5.8 million cubic feet of stone and brick and around 250 laborers, says Charloux.

Per McClatchy’s Moira Ritter, the researchers estimate the wall was used for at least four centuries before inhabitants abandoned it between 1626 and 1542 B.C.E.

Archaeological work in Khaybar is ongoing, and Charloux tells Live Science that the researchers will reveal more information in upcoming publications.

Sonja Anderson | READ MORE

Sonja Anderson is a writer and reporter based in New York City.