The pyramids of Egypt were built next to a branch of the Nile that has disappeared

The pyramids of Giza and 27 others located around it were built on the banks of a now-vanished branch of the Nile, covered by desert sand and farmland.

Oliver Thansan
Oliver Thansan
15 May 2024 Wednesday 22:57
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The pyramids of Egypt were built next to a branch of the Nile that has disappeared

The pyramids of Giza and 27 others located around it were built on the banks of a now-vanished branch of the Nile, covered by desert sand and farmland. The discovery, the result of a combination of satellite images, geophysical analysis and the study of sediments, shows the importance that the river had for Egyptian societies of the past, both as a cultural artery and to transport construction materials.

In an article published this Thursday by the magazine Communications Earth

The scientists who made the discovery have named the extinct river arm, 64 kilometers long, Ahmarat, which means pyramid in Egyptian. Located near the ruins of Memphis, once the capital of Ancient Egypt, the river linked the 31 temples distributed between El Lisht and Giza. Its existence solves the mystery of why these constructions are concentrated in a narrow strip in the middle of what is today an inhospitable desert.

The transportation of materials and labor to build the pyramids required a river that, until now, had remained hidden. Ahmarat has revealed that the river branch was not only key in the construction of the pyramids, but also in receiving visitors. Each pyramid complex was directly connected to the river by causeways perpendicular to its course, which ended in a temple located at the edge of the water that acted as a port.

The position of each pyramid is not random either, but reflects the changes in climatic conditions over the 1,000 years during which the buildings were built. When the first were erected, 4,700 years ago, the flow of the river arm was very high, so these pyramids are far from the river and located on high ground, to protect themselves from floods.

As the years of construction progress, the pyramids are found increasingly closer to the river and on lower ground, reflecting the reduction in flow, accelerated 4,200 years ago by a drought that limited the availability of water to almost dry the branch. The latest constructions, 3,600 years old, are touching the shore of what was Ahmarat.

The Synthetic Aperture Radar (SAR) equipped on board Sentinel-1, a satellite of the European Space Agency, has been key to the discovery of the extinct river branch. It is an instrument that emits radio waves that pass through layers of fine sand, bounce off more compact natural and artificial structures located below, and return to the satellite. The result is a high-resolution image of the desert subsurface, and a way to unearth secrets hidden beneath the sand.

This, the authors indicate, constitutes a very useful tool to make excavations more efficient. Satellite images indicate points of archaeological and anthropological interest, which can then be exploited in situ. In fact, it is something that researchers have done in the layout of Ahmarat.

Once the 64 kilometers of river branch were located, they have analyzed a stretch of just one kilometer with geophysical techniques to validate the satellite results. They have also studied the sediments from two specific points to more accurately describe the composition of the ancient river bed.

Beyond improving research efficiency, the experts suggest in the article using these satellite imaging techniques to protect ancient yet undiscovered settlements from the rapid urbanization of today's Egypt. It is likely, they say, that unknown towns and cities were built on the shores of Ahmarat that finer analyzes should be able to detect.