Scientists say they have finally solved mystery of how the ancient Egyptians built the pyramids.
The world has been baffled for thousands of years about just how slave workers transported the massive blocks across the Valley of the Kings in around 2,000BC.
Now physicists have come up with a two word answer after years of calculations - 'wet sand'.
Dutch researchers have figured out the Egyptians placed heavy objects on a sledge, pulled by hundreds of workers, and simply poured water on the sand in front of it.
Experiments at the University of Amsterdam proved the correct amount of dampness in the sand halves the pulling force required.
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Quite simply, dry sand would have piled up in front of the sledge, making it impossible to move.
But it would glide over wet sand which, with the correct amount of water becomes as stiff as dry sand and the sledge glides more easily over it.
The team, which constructed a laboratory version of the sledge on sand, said: “The Egyptians were probably aware of this handy trick.
“A wall painting in the tomb of Djehutihotep clearly shows a person standing on the front of the pulled sledge and pouring water over the sand just in front of it."
But the research of how they ancients managed to do it, could also have a modern-day use to optimise the transport and processing of granular material which, at present accounts, for about ten percent of the worldwide energy consumption.