Did These Mysterious Structures Belong to an Ancient Arabian Religion?

Arabia’s mysterious “mustatils”—massive structures made from loose rocks piled into walls on desert hilltops and highlands—are the remnants of an ancient religion that spread across the region about 7,000 years ago, according to a study. The research found similarities across different sites in animal offerings at mustatils, which predate Stonehenge by more than 2,000 years, suggesting that the people who built them shared ritual beliefs.

The strange enclosures are often rectangular—“mustatil” is Arabic for rectangle—and thousands have been identified throughout Saudi Arabia. Mustatils vary in size, but they are typically huge: Some stretch more than 1,900 feet long. Most feature a long courtyard with one or more entrances at one end. As the Art Newspaper notes, many of these chambers contain standing stones.

Studies show they share a specific layout, with platforms of piled rocks along each short edge of the massive rectangle, connected at right angles to the longer sides by low walls. Over time, the stone structures have partially collapsed, so the walls and platforms are now only a few feet high. They surround courtyards of exposed bedrock that seem to have been empty.

Mustatils were constructed from loose rocks in the same way as the region’s many desert kites, which experts think were prehistoric traps for wild herds. But mustatils are very unlike the sprawling kites, says archaeologist Huw Groucutt of the University of Malta. “Desert kites and mustatils have a very different kind of shape,” he explains. “They appear quite distinct.”

Local people probably knew about many of the mustatils, but they were first officially recorded in the 1970s during aerial surveys in Saudi Arabia. Their truly strange nature was only revealed, however, in later close-up archaeological studies.

A September 2026 study examined 28 mustatils near the desert town of Al-Thamad in the Harrat Khaybar region, a basalt highland of ancient lava fields about 75 miles north of Medina. The researchers compared them with mustatils previously studied in the AlUla region, about 120 miles to the northwest.

The key finding was that every mustatil contained chambers in one of the platforms with the remains of the same type of offering. The offerings consisted of the severed heads of horned animals—usually domesticated cattle, but sometimes goats or wild gazelles—with no lower jaws or other body parts.

That indicates that the same rituals were conducted at each mustatil, says archaeologist Melissa Kennedy of the University of Sydney in Australia, the study’s first author.

“The most convincing evidence to us that the mustatils represent a large-scale, cohesive practice is that so far, every site yields the exact same body of material,” she says.

“Unlike food refuse, which typically contains a broad variety of skeletal elements, these finds consist solely of upper cranial elements. This high level of selectively strongly indicates a target practice driven by a shared concept.”

Kennedy’s team identified four distinctive types of mustatils in the Harrat Khaybar region, based on ground and aerial surveys. The “classic” form, also seen at AlUla and elsewhere, has a simple, narrow entrance to the enclosure through one of the platforms. Another type has “low crawling tunnels” through one of the platforms, which seem to have acted like a maze for people entering the site. A third has an oval chamber and stone pillars within the entrance platform. In the fourth type, the entrance platform curves outward into a crescent shape.

Researchers are not sure what these differences mean. They may be linked to specific events, seasons or other factors, says Kennedy. “While we may never know for certain…the fact that many were constructed concurrently suggests that these stylistic choices held distinct social or ritual meanings,” she says.

Radiocarbon dating from the Al-Thamad mustatils also showed that they were about 500 years younger than the mustatils at AlUla to the north. Kennedy says this suggests the mustatil tradition may have originated in AlUla or farther north before spreading south. Arabia was much greener 7,000 years ago than it is today, and researchers believe the region was inhabited by seminomadic people who hunted wild animals and herded domesticated livestock.

Groucutt stresses that much of Arabia is geographically remote and poorly understood, making studies like this especially important. “The combination they’re applying of surveys with helicopters, drones and so on...is exactly the kind of method we need,” he says.

But many mysteries about mustatils remain, Groucutt says, because archaeology can only provide a “partial record” of the activities that went on there. “What we’re interested in is like human behavior, social practices, languages, cultural systems " he says, adding, "not much of that preserves.”