Egypt’s iconic pyramids have been a source of mystery and wonder for thousands of years, as experts have scrambled to understand how an ancient society could be capable of building such colossal structures.
Now, archaeologists have uncovered a crucial piece of the construction puzzle – a long-lost branch of the Nile River, buried beneath desert sands for millennia, that could finally explain how the ancient Egyptians transported massive stones (some of which weigh upwards of 10 tonnes) to build these monuments.
The discovery, detailed in a new study published in Nature Communications Earth & Environment, sheds light on the puzzling location of 31 pyramids, including the famed Giza complex.
These pyramids sit on the edge of the harsh Sahara Desert, far from the modern Nile – a seemingly odd location to our modern eyes. The newly identified 64-kilometre-long branch, dubbed the 'Ahramat' (meaning 'pyramids' in Arabic), would have provided a vital water route for transporting building materials directly to the pyramid sites.
"Many of us who are interested in ancient Egypt are aware that the Egyptians must have used a waterway to build their enormous monuments," lead author Prof Eman Ghoneim told BBC Science Focus, “but nobody was certain of the location, the shape, the size, or proximity of this mega waterway to the pyramids site.”
Modern techniques reveal hidden history
To find the mystery waterway, the team first relied on radar satellite data.
“Unlike aerial photos or optical satellite sensors that image the land surface, radar sensors image the subsurface due to their unique ability to penetrate the sand surface and produce images of hidden features including buried rivers and ancient structures,” Ghoneim said.
Researchers then confirmed the presence of river sediments and former channels using on-the-ground geophysical surveys and sediment core analysis.
At the time of the pyramids' construction, the hidden branch would have been a bustling highway, 64 kilometres long, around half a kilometre wide and at least 25 metres deep.
The team’s work suggests that the branch’s days were numbered following a major drought some 4,200 years ago, which contributed to it drying up and silting over. This time frame coincides almost perfectly with the end of the sixth dynasty (around 2340 BC), when pyramid construction largely halted.
Adding to the weight of evidence is the fact that many pyramids had ceremonial causeways leading up to them. According to the study, these causeways ran perpendicular to where the Ahramat Branch once ran, terminating exactly where the riverbanks once lay.
The findings not only shed light on the logistical prowess of ancient Egyptians but also underscore the vital role of the Nile as a cultural and economic artery. Moreover, the authors highlighted how the Egyptians, much like us, were affected by environmental change in what was once the cultural centre of their civilisation.
“We hope that our research effort here will contribute to the unanswered questions about the building of the pyramids and the ancient landscape," Ghoneim said.
Looking ahead, Ghoneim and her team are planning to use their high-tech approach to uncover more lost branches of the Nile, and with them a treasure trove of archaeological findings along their banks.
About our expert
Eman Ghoneim is a professor in the Department of Earth and Ocean Sciences at University of North Carolina Wilmington. Her primary interest is in the application of Geographical Information Systems (GIS), Remote Sensing and the use of hydrologic modelling in flash flood hazard, groundwater exploration in desert environments and present sea level rise simulation. Ghoneim is the principal investigator on the project to uncover lost branches of the Nile which has received grants from the National Science Foundation as well as the Explorer Club and Warner Brothers Discovery.
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