Researchers have uncovered a potential explanation for how the iconic Pyramid of Djoser, believed to be the oldest in ancient Egypt, was built.
The step pyramid, located in the Saqqara necropolis, which lies on a limestone plateau on the west bank of the Nile River, may have been constructed with the help of an ingenious hydraulic lift system, a study published in the journal PLOS ONE proposes.
The study authors suggest this system involved water flowing into two shafts located inside the pyramid itself, enabling a float to be raised and lowered in order to lift the large stones used to build the structure.
"This discovery provides a coherent answer to a question about the construction of the pyramids that has remained unanswered for several centuries," study lead author Xavier Landreau, from CEA Paleotechnic Institute, France, told Newsweek.
The Pyramid of Djoser is thought to have been built around 4,700 years ago as a funerary complex for Pharaoh Djoser of ancient Egypt's Third Dynasty.
"We see it as a technological prototype," Landreau said. "Its architecture is revolutionary, with many innovations, making it a technological precursor to the Cheops pyramid. It is the first to disclose two crucial innovations: a pyramid shape and the exclusive use of fully dressed stones for masonry."
Once completed, the pyramid stood more than 200 feet high, making it the tallest man-made structure in the world at the time, as far as we know. But exactly how the pyramid was constructed remains unclear.
The latest study, however, sheds light on this question. The first key finding of the work is that the Djoser Step Pyramid was built below a watershed and potentially had access to a significant water supply at the time.
In the paper, the authors also show that a massive, previously unexplained structure close to the pyramid, known as the Gisr el-Mudir enclosure, displays features of a "check dam" designed to trap sediment and water. Measuring nearly 2 kilometers (1.2 miles) in length and 15 meters (49 feet) thick, it would have regulated and filtered water while providing protection against torrential floods for the Saqqara plateau below, the study proposes.
In the southern part of the moat surrounding the Djoser complex, the researchers then turned their attention to a monumental excavation known as the "Deep Trench"—measuring around 1,312 feet long and 88 feet deep—cut entirely out of the rock, with a hitherto unexplained function.
By cross-referencing hydrological analyses and past archaeological findings, the team propose that this structure, which comprises several successive compartments, combines all the technical features of a water treatment plant.
"Taken as a whole, the Gisr el-Mudir and the Deep Trench form a unified hydraulic system that enhances water purity and regulates flow for practical uses and vital needs," Landreau said.
Finally, the team uncovered evidence that the internal architecture of the Saqqara Step Pyramid is consistent with a never-before-reported hydraulic elevator mechanism, according to the study.
"We have shown that sediment-free water from the Deep Trench treatment plant would have been introduced into underground conduits beneath the Djoser pyramid. These conduits...had remained unexplained until now," Landreau said.
"Through this hydraulic network, water would have been guided to the central well beneath the pyramid and, through filling and draining cycles, raised a float carrying stones. Djoser's pyramid would have been erected like a volcano, with building materials arriving at its central axis."
Such a system would have had provided several advantages, according to Landreau. For example, it would have minimized the workload of site laborers by enabling large quantities of stone to be lifted vertically with each filling/emptying cycle of the shaft.
"It is almost like a crane on our modern building sites," Landreau said. "Its position inside the pyramid also offers logistical advantages, as the blocks arrive at the structure's central axis, allowing for natural, volcano-like construction and making it easy to give the whole thing a pyramid shape."
While the latest findings shed light on a possible construction method, the findings also prompt new questions.
"This work opens up a new line of research for the scientific community: the use of hydraulic power to build the pyramids of Egypt," Landreau said. "It not only piques curiosity about the level of technical knowledge possessed by the architects of these structures, surpassing previous estimations, but also challenges the established historical narrative."
Further research is still required to confirm the hydraulic lift hypothesis. For example, additional studies need to investigate how the hydraulic system may have functioned, and determine how much water was available in the landscape at that time. But while the authors suggest that other methods, such as ramps and levees, may have been used to help build the pyramid, they propose that the lift system could have been employed to assist in the construction when sufficient water supply was available.
"We know that ancient Egypt was a 'hydraulic civilization' skilled in managing irrigation canals and transporting heavy stones over long distances," Landreau said.
Whether other ancient Egyptian pyramids were constructed with a similar hydraulic lift mechanism is currently uncertain, but possible, according to the researcher.
"As authentic sources from the working sphere of pyramid architects are currently lacking, no generally accepted holistic model for pyramid construction exists yet," Landreau said. "Although many detailed publications dedicated to pyramid-building procedures have [provided] tangible elements, they usually explain more recent, better documented, but also smaller pyramids. These techniques could include ramps, cranes, winches, toggle lifts, hoists, pivots, or a combination of them."
"Further investigation is warranted, as [hydraulic lift systems] may hold the key to uncovering the mystery of how the largest monoliths, found in pyramids like Khufu or Kephren, were raised," he said. "These monoliths weigh tens of tons, making it seemingly impossible for them to be hauled using manpower alone. Conversely, a moderate-sized hydraulic lift can raise 50 to 100 tons. Exploring concealed shafts within these pyramids could be a promising avenue for research."
Do you have a tip on a science story that Newsweek should be covering? Do you have a question about archaeology? Let us know via science@newsweek.com.
Disclaimer: The copyright of this article belongs to the original author. Reposting this article is solely for the purpose of information dissemination and does not constitute any investment advice. If there is any infringement, please contact us immediately. We will make corrections or deletions as necessary. Thank you.
