The Great Pyramids of Giza
"Soldiers! From the top of these Pyramids, 40 centuries are looking at us."
Napoleon on his invasion of Egypt, 1798
Out of the 80 known pyramids situated on the west bank of the Nile, the most famous is the Great Pyramid. Probably the most comprehensively surveyed archaeological treasure of the known world, the Great Pyramid has romanced the imaginations of writers, politicians, mathematicians and religious leaders over the centuries. The Great Pyramid and its surrounding structures are in Giza, a suburb of Cairo, the largest city in Africa. What we know of the builders of the pyramids changes every day as new archaeological finds are uncovered in the desert.
Herodotus, the Greek historian was the earliest known documentor of the Pyramids. However, even he visited the pyramids 2,700 years after they were built in the 5th century BC and much of his reporting was based on hearsay. According to him, 100,000 people were involved in the construction.
In
816 AD Caliph al-Mamun carried out what was probably the first excavation
of the site when he ordered workers to blast through the blocked stone
entrance. Isaac Newton got there early. He found out that many of the
key pyramid measuremens would be in round numbers if the Sacred Jewish
Inch was used instead of the British inch. The Sacred Jewish Inch is 1/25
of a cubit and the equivalent of 1.00106 British inches.
Egyptologist Sir William Matthew Flinders Petrie conducted an exhaustive survey of the pyramids in 1881. He determined the exact dimensions of the sides of the Pyramids and he found that they were almost exactly the same length to a accuracy of 0.1 +/- inch. He also found that the dimensions of the King's Chamber embodied geometry that preserved the 3:4:5 triangle ratios discovered by Pythagoras in the 6th century BC (Collins, 1998).
When it was built, the Great Pyramid was 145.75m (481feet) high, although over the years it lost 10m (30feet) off the top. It was the tallest structure of the pre-skyscrapian world, orientated to the 4 cardinal points. Egyptologists say it was commissioned in 2,550 BC (4th dynasty of Egypt's Old Kingdom) by King Khufu. 2 million blocks of stone weighing an average of 2.5 tons each were used in its construction, with the heaviest being 60 tons. How did they do this? The popular belief right now is that the builders employed slave labour and the use of gradually sloping ramps to move the blocks into place. The pyramid used to have polished casing stones which were carted off by the Arabs 600 years ago.