There has long been a debate – how were the pyramids of ancient Egypt built by the first engineers in the civilized world?
A popular view is that they used a system of ropes and sleds to pull the stones to the top, building them layer by layer as the pyramids moved up from the ground.
But a new study shows that Egypt's oldest pyramid, the Pyramid of Djoser, was built 4,700 years ago using a more ingenious "hydraulic lift."
"The ancient Egyptians were known for their pioneering spirit and mastery in hydraulic engineering, using canals for irrigation and barges to transport huge stones," the research team explained.
"This work opened up a new field of research – the use of hydraulic power to construct the massive structures built by the pharaohs."
The new theory was proposed by a new study led by Xavier Landreau, director of the archaeological institute Paleotechnic in Paris, France.
The researchers studied historical records and satellite photographs of the area to explain the features that supported their arguments.
"We determined that the internal structure of the stepped pyramid was consistent with a hydraulic lifting mechanism that had never been reported before," Landreau and his colleagues said.
"Ancient architects may have used sediment-free water to raise stones from the center of the pyramid in the manner of a volcanic eruption."
Standing about 200 feet tall, the Pyramid of Djoserl is a "step pyramid" – meaning that it is flanked by a series of flat platforms or steps, unlike the flatter sides of the famous Pyramid of Giza.
While the Pyramids of Giza are the largest pyramids in Egypt, the Pyramid of Djoserl is the oldest, having been built between about 2667 and 2648 BC.
Built entirely of stone, this stunning structure was built by ancient Egypt architect Imhotep at the Saqara Necropolis in southern Cairo.
It is believed to be the final resting place of Drosel, the ancient Egypt pharaoh who was the founder of the Kingdom of Ancient Egypt.
While a huge shaft in the center of the pyramid is already known, researchers are now proposing new theories about its use.
First, they point to Gisr · Moodir, an ancient stone structure located less than a mile west of the Pyramid of Djoser.
The function of Gisr · has never been determined, but researchers say it may have acted as a dam, collecting rainwater and directing it to the pyramid through a pipe system.
Once the groundwater reaches the center of the pyramid, it scours upwards through the central shaft like magma in a volcano.
This powerful column of water pushes a floating elevator – a horizontal platform that may be made of wood – that can carry up to 100 tons of stone at a time due to the power of the water.
According to experts, it is possible to control the water column so that the shaft can be emptied, ready to use another batch of stones again.
Probably, the water could be plugged like some kind of plug at the bottom of the pyramid shaft, and then released when the next batch of stones was in place.
While this newly proposed system may seem particularly complex for 4,700 years ago, the pyramids themselves are evidence that the ancient Egyptians may have been more skilled engineers than we thought.
Gisr · Mudir was previously thought of as a bullpen, a ceremonial site for the worship of gods, and even an unfinished pyramid.
But the theory that it is a dam provides a striking link to the central shaft of the Pyramid of Djosel, which reopened to visitors in 2020 after 14 years of restoration.
It is unclear whether other famous pyramids in Egypt used this construction technique; MailOnline has reached out to the experts for more information.
New research outlining this theory has been published in the journal PLOS One.