Anish Vij
Scientists reckon they've got the most convincing theory on how the ancient pyramids were built - and we are all ears.
For thousands and thousands of years the Egyptian pyramids have baffled us, I mean seriously - how the heck were they made?
What we do know is that many of the 100-odd pyramids were built as tombs for the country's pharaohs - and around 2780 BCE - the first pyramid was built on near the ancient city of Memphis.
Since then, we don't really know much else.
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That's until physicists from the University of Amsterdam began analysing an old wall painting from the tomb of Djehutihotep, dating back to around 1900 B.C.
In a 2014 study, published in the journal Physical Review Letters, scientists said the construction of the pyramids might actually be quite simple.
The image in question shows how 172 ancient Egyptians managed and moved those massive stones.
You can also see a worker pouring water on the sand in front of a sled that's carrying a colossal statue.
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And it turns out that the sleds were not just large wooden planks.
"Egyptologists had been interpreting the water as part of a purification ritual," physicist Daniel Bonn told The Washington Post.
"And had never sought a scientific explanation.
"Friction is a terribly complicated problem; even if you realise that wet sand is harder — as in a sandcastle, you cannot build on dry sand — the consequences of that for friction are hard to predict."
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He said the experiment not only solved 'the Egyptian mystery, but also shows, interestingly, that the stiffness of sand is directly related to the friction force'.
Sorry folks, no aliens this time.
"We show experimentally that the sliding friction on sand is greatly reduced by the addition of some—but not too much—water," the study reads.
"The formation of capillary water bridges increases the shear modulus of the sand, which facilitates the sliding.
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"Too much water, on the other hand, makes the capillary bridges coalesce, resulting in a decrease of the modulus; in this case, we observe that the friction coefficient increases again.
"Our results, therefore, show that the friction coefficient is directly related to the shear modulus; this has important repercussions for the transport of granular materials.
"In addition, the polydispersity of the sand is shown to also have a large effect on the friction coefficient."