Ancient stone structures in Saudi Arabia older than previously thought Peter Donnelly A significant archaeological discovery in Northwest Saudi Arabia shows a monumental, complex of structures called mustatils that are more ancient than previously believed, a specialist research body revealed Thursday. The Kingdoms Institute, the recently unveiled center for archaeological research and conservation studies in AlUla, made the announcement. While the existence of the mustatils was previously known, the more than 1,000 mustatils that the RCU-commissioned team recorded are roughly twice as many as were previously identified. The aerial and ground research led by a team from the University of Western Australia surveyed vast stretches of the region by remote sensing and helicopter. After recording their presence from the air, the team then explored some 40 at ground level and excavated one – altogether constituting the largest study of mustatils to date. These ancient structures in the Arabian desert provide early evidence of ritual activity.