How the Egyptian pyramids were built has long been a mystery. Constructed as tombs for the pharaohs over 4,000 years ago, more than 100 of them remain. The largest one, the Great Pyramid of Giza, was originally 147m tall (482ft). It's made up of about 2.3 million stone blocks, each weighing between 2.5 and 15 tonnes, and would have had to be transported to the building site and lifted into place with techniques available at the time. To put this into context, it's akin to lifting a double-decker London bus to the top of St Pauls Cathedral a few million times.
There's still debate between scientists on the exact method of raising these heavy blocks to such great heights, says Dr Eman Ghoneim, a professor at the University of North Carolina Wilmington in the US.
Recent research is helping to fill in pieces of the puzzle, however. The most widely accepted theory is that ramps were used to haul the stones up, and it's supported by remains of inclined structures found close to some of the pyramids. But the steepness of these ramps has been the subject of debate.
In 2018, Dr Roland Enmarch, a senior lecturer in Egyptology at the University of Liverpool and his team made a breakthrough by discovering a ramp cut into rock at a quarry at Hatnub, in the Eastern Desert of Egypt, which was an important source of alabaster used in the pyramids. The angle of the ramp was more extreme than expected, with a slope of more than 20 per cent (previous estimates suggested that ramps in Ancient Egypt wouldn't have exceeded 10 per cent). The team was studying inscriptions at the quarry that date back to the time the Great Pyramid was built, suggesting that a similar ramp could have been used in its construction.
This story is from the September 2024 edition of BBC Science Focus.
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This story is from the September 2024 edition of BBC Science Focus.
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