4,000-year-old wall found around oasis in Saudi Arabia likely defended 'against raids from nomads'

A reconstruction of a walled fortification with trees and fields in the center.
A reconstruction of what the fortification wall may have looked like. (Image credit: © Khaybar LDAP, M. Bussy & G. Charloux, CC Attribution 4.0 International)

A giant wall dating back around 4,000 years has been discovered surrounding an oasis in Saudi Arabia.

The wall was originally 9 miles (14.5 kilometers) long and surrounded the Khaybar Oasis, located near the city of Al-'Ula. It was about 16 feet (5 m) high and 5.6 to 7.9 feet (1.7 to 2.4 m) thick, the team said in a statement.

The wall originally had 180 bastions, points projecting out of the fortification.  Radiocarbon dating of charcoal remains found during excavations indicate that the wall dates to between 2250 and 1950 B.C., the team wrote in a paper published Jan. 10 in the Journal of Archaeological Science: Reports. Pottery remains on the wall also suggest that it dates to around that time. The wall may have been used for a few centuries before being abandoned.

Today, only about 3.7 miles (5.9 km) of the 9-mile wall and 74 of the 180 bastions remain, the team said in the statement.

Related: 7,000-year-old cult site in Saudi Arabia was filled with human remains and animal bones

Part of the wall with a bastion was found in Saudi Arabia. (Image credit: © Khaybar LDAP K. Guadagnini, CC Attribution 4.0 International)

Why were they built?

The wall may have been constructed for several reasons. One likely purpose was military defense "against raids from nomads," Guillaume Charloux, an archaeologist with the French National Center for Scientific Research (CNRS) and lead author of the paper, told Live Science in an email.

In their paper, the scientists noted that the people who built the wall may have used it to demarcate their territory and to protect against flash floods. The team noted that other examples of fortified oases have been found on the Arabian Peninsula and may be a sign that populations were becoming more sedentary.

It would have taken 5.8 million cubic feet (164,000 cubic meters) of stone and brick and about 250 people working for four years to build the wall, Charloux said.

Work in the Khaybar Oasis is ongoing, and Charloux said we can expect to hear of results discussing a sizable settlement that existed in the Khaybar Oasis. There "is another important publication to come," he said.

Before the excavations were conducted, the site was analyzed using satellite surveys. The work on the fortifications was carried out between 2020 and 2023 by researchers with the Khaybar Longue Durée Archaeological Project.

Owen Jarus
Live Science Contributor

Owen Jarus is a regular contributor to Live Science who writes about archaeology and humans' past. He has also written for The Independent (UK), The Canadian Press (CP) and The Associated Press (AP), among others. Owen has a bachelor of arts degree from the University of Toronto and a journalism degree from Ryerson University.