In the hills of north-west Morocco, overlooking the river that gives the site its name, research at Oued Beht is bringing to light a previously unknown chapter of the region’s past. The discovery of a substantial built structure suggests that, during the second millennium BC, communities in north-west Africa were actively shaping their environment. They were also engaging in broader networks of interaction across the Mediterranean world.Previous research by the Oued Beht Archaeological Project had already brought to light what is likely the earliest and largest agricultural complex ever discovered in Africa outside the Nile Valley. It dates to around 5,400 to 4,900 years ago. New excavations carried out in 2023 – in which we took part – have now deepened our understanding of the site.Our new study shows how we uncovered the earliest known large-scale construction of a probably defensive nature in north Africa beyond the Nile Valley. It’s about 4,000 to 3,500 years old.It’s not known exactly what threats these wall-like structures were designed to counter. They likely relate to increasing competition over land, resources, and possibly control of movement through the landscape, rather than to “invaders”. Constructions like these suggest communities felt the need to protect themselves or assert power over strategic locations. This discovery pushes back the evidence for organised defensive architecture in the Maghreb and suggests that societies in this region at this time were more complex and structured than previously believed.Our study also reveals how the ridge of Oued Beht would become a focal point again in the medieval period, during the 11th to 13th centuries AD. The same defensive structure was rebuilt, a hamlet or farm was established on a nearby hilltop, and people were buried in a cemetery between the two areas. Read more: A 5,000-year-old farming society in Morocco fills a major gap in history – north-west Africa was a central player in trade and culture Together these findings provide rare archaeological insights into rural communities during both prehistoric and medieval times. They help us understand how societies developed and maintained themselves in a region too often left out of the history books. A prehistoric hub in the MaghrebFor a long time, the later prehistory of north Africa’s Maghreb region (the Mediterranean countries of Morocco, Algeria, and Tunisia) has been poorly understood. Compared with neighbouring areas such as Iberia in south-western Europe or Athens in the eastern Mediterranean, archaeological evidence was often fragmentary. In the last few years this has changed completely. Excavations at Oued Beht have revealed a large concentration of human activity spread across at least ten hectares. The earliest major phase dates to the mid-fourth and early third millennia BC, or the Final Neolithic period.Environmental evidence from plant and animal remains in the prehistoric era indicates a farming community cultivating crops such as barley and wheat. They also exploited wild plants and kept livestock.The site was also an important centre of craft production. Thousands of polished stone axes and other tools have been discovered, along with finely made pottery, sometimes decorated with painted patterns. It’s still uncertain whether prehistoric Oued Beht functioned as a permanent village, a seasonal centre, or something less familiar. But it was clearly a major focus in the landscape of north-west Morocco.The defensive wallThe presence of potentially ancient earthworks and walls had been noted since the 1930s. The French archaeologist Armand Ruhlmann first documented a configuration of three walls, with the fourth side protected by the natural scarp of the ridge, describing a defensive éperon barré (barred spur). Their precise nature and date remained uncertain until now.New excavations have clarified the existence of a multi-phase ditch, rampart and wall built across a narrow section of the Oued Beht ridge between the river and a ravine. This cut off and protected the ridge’s southern tip. Radiocarbon dating of deposits associated with these structures gave us the timelines in our study.They place its original construction at a time equivalent to the Bronze Age of the remaining western Mediterranean. This makes it the earliest confirmed defensive construction in north Africa outside Egypt.What was this construction for?This structure raises important questions about the society that built it. Building an embankment and ditch system required planning, coordination and the mobilisation of labour. This suggests a community capable of organising complex construction initiatives.During the earlier Neolithic phase, activity at Oued Beht focused on the larger and more open northern area of the site. By the period of our new study, focus had shifted to the narrower, more defensible southern ridge. This may reflect a shift in settlement strategies.Mediterranean connectionsThe second millennium BC was a dynamic period across the Mediterranean. In southern Iberia, Argaric societies (about 2200-1550 BC) in today’s Europe were developing complex, often hilltop settlements. They were characterised by planned architecture, advanced metallurgy (especially bronze production), and marked social hierarchies visible in burial practices. These communities often constructed fortified sites, and strategically located settlements controlling surrounding territories.Increasing evidence suggests that communities in north-west Africa were connected to wider Mediterranean networks. This includes today’s Spain and Portugal. The discoveries at Oued Beht indicate that the Maghreb was not isolated. It participated in broader processes shaping the western Mediterranean. The defensive system at the site may reflect wider transformations in social organisation and regional interaction. There may have been growing competition over resources, control of movement, and more formalised leadership structures.Rewriting historyThe discoveries at Oued Beht highlight how much remains to be learned about the deep history of north Africa. The defensive wall shows that communities here were able to coordinate large construction projects and points to social transformations that are only very tentatively beginning to be recognised. Read more: Discovery of a 4,000-year-old Bronze Age settlement in Morocco rewrites history The medieval remains demonstrate that the ridge was used again many centuries after the prehistoric settlement had been abandoned. Oued Beht was not simply a single-period settlement but a landscape repeatedly selected by different communities across millennia. As research continues, this location may become key to understanding how societies in the Maghreb evolved from early farming communities to the medieval rural world.Giulio Lucarini received funding for the OBAP from the Italian Ministry of Foreign Affairs and International Cooperation (MAECI), the National Research Council of Italy, and the Italian Ministry of University and Research (MUR), via ISMEO - The International Association for Mediterranean and Oriental Studies, Rome. He is affiliated with ISMEO.Cyprian Broodbank received funding for the OBAP from the British Institute for Libyan and Northern African Studies, a Cambridge University Humanities Research Grant, and the McDonald Institute for Archaeological Research. He is a trustee of the Mediterranean Archaeological Trust and Museum of London Archaeology.Toby C. Wilkinson is affiliated with the McDonald Institute for Archaeological Research, University of Cambridge and the Catalan Institute for Classical Archaeology (ICAC).