Did Canals Help Build Egypt's Pyramids?

How were the Pyramids built? NBC News reported on 'a possible answer' after new evidence was published earlier this year in the journal Communications Earth & Environment.
The theory? '[A]n extinct branch of the Nile River once weaved through the landscape in a much wetter climate.'

Dozens of Egyptian pyramids across a 40-mile-long range rimmed the waterway, the study says, including the best-known complex in Giza. The waterway allowed workers to transport stone and other materials to build the monuments, according to the study. Raised causeways stretched out horizontally, connecting the pyramids to river ports along the Nile's bank.

Drought, in combination with seismic activity that tilted the landscape, most likely caused the river to dry up over time and ultimately fill with silt, removing most traces of it.

The research team based its conclusions on data from satellites that send radar waves to penetrate the Earth's surface and detect hidden features. It also relied on sediment cores and maps from 1911 to uncover and trace the imprint of the ancient waterway. Such tools are helping environmental scientists map the ancient Nile, which is now covered by desert sand and agricultural fields... The study builds on research from 2022, which used ancient evidence of pollen grains from marsh species to suggest that a waterway once cut through the present-day desert.
Granite blocks weighing several tons were transported hundreds of miles, according to a professor of Egyptology at Harvard University — who tells NBC they were moved without wheels. But this new evidence that the Nile was closer to the pyramids lends further support to the evolving 'canals' theory.

In 2011 archaeologist Pierre Tallet found 30 different man-made caves in remote Egyptian hills, according to Smithsonian magazine. eventually locating the oldest papyrus rolls ever discovered — which were written by the builders of the Great Pyramid of Giza, describing a team of 200 workers moving limestone upriver. And in a 2017 documentary archaeologists were already reporting evidence of a waterway underneath the great Giza plateau.

Slashdot reader Smonster found an alternate theory in this 2001 announcement from Caltech:

Mory Gharib and his team raised a 6,900-pound, 15-foot obelisk into vertical position in the desert near Palmdale by using nothing more than a kite, a pulley system, and a support frame... One might ask whether there was and is sufficient wind in Egypt for a kite or a drag chute to fly. The answer is that steady winds of up to 30 miles-per-hour are not unusual in the areas where the pyramids and obelisks are found.

'We're not Egyptologists,' Gharib added. 'We're mainly interested in determining whether there is a possibility that the Egyptians were aware of wind power, and whether they used it to make their lives better.'

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