Greatest Feats of Engineering Part 4: The Great Pyramids of Giza

Last week on my 'Greatest Feats of Engineering' I talked about the Three Gorges Dam, an enormous dam and hydroelectric power station in China.

This week I’ll be looking at the Great Pyramids of Giza, one of the most well known contenders in this competition and one I had the pleasure of personally visiting in 2001. Believe me, after experiencing north Africa in August I will never again complain about even the driest of British summers.

The Great Pyramids form part of the Giza Necropolis and rest on the Giza Plateau some 25km from Cairo, Egypt. It was strange to visit them, as school had always led me to believe they would be sitting solitary in the desert when in fact you can see them driving through the City.

The complex consists of six pyramids in total, the pyramids of Khafre (distinguishable by it's limestone cap stones), Menkaure and Khufu as well as three smaller 'queen's' pyramids as part of Khufu's pyramid complex. The complex also contains the Great Sphynx, dated to the reign of King Khafre approximately 4540 years ago.

The Pyramids were primarily made of stone quarried locally with a layer of fine, white limestone brought across the Nile and used to build the exteriors. Scholars are still debating the method by which the pyramids were constructed and particularly the way in which the exterior stones were aligned and fitted together. To preserve the symmetry of the pyramids every stone had to be of equal width and height and it is still uncertain as to wether they were cut and then placed or if they were placed and then cut to match the surrounding stones.

The pyramids were all built along a north to south and east to west alignment, accurate to within a few degrees; imagine trying to achieve that level of precision without the assistance of modern equipment.

It is believed that each Pyramid took around 30 years to build and that shifts of labourers 10,000 strong and working in 3 month shifts were needed for the construction. It had previously been thought that these workers were slaves, but more recent evidence suggests that they were paid labourers and that they took great pride in their work.

So what makes this a feat of engineering? Whilst it certainly lacks the complexity of the LHC or the utility of the Three Gorges Dam the Great Pyramids are no less a colossal achievement. The precision involved in their construction, both in the alignment of the base and the interlocking exterior stones would be challenging today with modern measurement and stone working tools, performing the same trick 4500 years ago when everything had to be done by hand and when navigation was primarily conducted using the stars as a reference point is staggering when seen on the scale of the pyramids.

The pyramids were also a huge feat of organisation, for a civilisation to be able to support the number of labourers, architects and artisans needed for such a project implies an extremely strong economy otherwise they would never have been able to feed such a large work force over such periods of time. Furthermore, try to imagine having to coordinate the work of 10,000 labourers, keeping in mind that the final result has to be accurate to within a handful of degrees.

Lastly there's the logistics of the construction itself to consider. The stones used in the pyramids construction averaged 1.5 tons each and the granite slabs used to roof the burial chambers themselves could weigh upto 80 tons. These stones had to be quarried, transported to site, cut and fitted by hand and given that the ancient Egyptians possessed no iron tools, nor wheels or pulleys and yet still managed this is incredible.

What do you think? Are the Great Pyramids of Giza your greatest feat of engineering? Cast your vote now!

Next week: The Great Wall of China.

References:

http://en.wikipedia.org/wiki/Egyptian_pyramid_construction_techniques#cite_note-46 http://en.wikipedia.org/wiki/Pyramids_of_Giza

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