Over 1000 massive stone structures scattered across a 200,000=kilometer-area near the city of AlUla in northwest Saudi Arabia (Credit: AAKSA and Royal Commission for AlUla)

A collection of 1,000 prehistoric structures dubbed mustatils — the plural form of the Arabic term for rectangles — scattered across 124,274 miles (200,000 kilometers) in northwest Saudi Arabia may be the world's oldest monuments. A team of archeologists from the University of Western Australia (UWA) reached this conclusion after radiocarbon dating of charcoal found inside the courtyards indicated they were constructed in 5,000 BC — or about 2,000 years before the Egyptian pyramids or monuments like Stonehenge in southern England.

"The mustatil phenomenon represents a remarkable development of monumental architecture, as hundreds of these structures were built in northwest Arabia," the researchers wrote in their paper, published in the journal Antiquity on April 30, 2021. "This 'monumental landscape' represents one of the earliest large-scale forms of monumental stone structure construction anywhere in the world."

The courtyards, which were initially called "Gates," were discovered in the 1970s. However, it is only recently that a team, led by Dr. Hugh Thomas, a UWA research fellow, closely examined the impressive structures as part of a program funded by the Royal Commission of AlUla’s (RCU) Aerial Archeology. Established by the government of Saudi Arabia in 2017, its primary purpose is to preserve the rich heritage of the AlUla region, where the mustatils are situated.

The mustatils varied in size and were constructed using sandstone (Credit: AAKSA and Royal Commission for AlUla)

The rectangular enclosures were made using massive blocks of sandstone, some weighing as much as 1,100 pounds (500 kilograms). Though they range from 49 feet (15 m) to about 2,021 feet (616 m) long, the walls all stand about 4 feet (1.2 meters) tall. This, together with the lack of artifacts, led the team to conclude that the courtyards were not occupied or used year-round. "It’s not designed to keep anything in, but to demarcate the space that is clearly an area that needs to be isolated,” says Dr. Thomas.

While many of the mustatils had been damaged, in 2019, the researchers found a well-preserved structure, complete with cattle, sheep, goat, and gazelle bones. The remains, all clustered around an upright stone in the center of a stone-walled chamber, led the researchers to theorize that the animals may have been used as offerings to appease gods.

The archeologists found animal remains in one of the mustatil's central chambers (Credit: AAKSA and Royal Commission for AlUla)

“We think people created these structures for ritual purposes in the Neolithic, which involved offering sacrifices of wild and domestic animals to an unknown deity/deities. Due to the monumental size of some of these buildings, this would have required considerable effort, so, likely, larger communities or groups of people came together to build them. This suggests significant social organization and a common goal or belief, " Dr. Thomas said.

The scientists, who plan to continue excavating the ancient structures, hope they will uncover more secrets about the ancient civilization that lived in the area over 7,000 years ago. UWA archeologist and study co-leader, Melissa A. Kennedy, is particularly keen on gaining more insights into the deities worshipped. The scientist says, “We may never know for sure, but it is an exciting avenue of research."

Resources: newscientist.com, livescience.com,news.yahoo.com,