The Great Pyramid of Giza (also called the Khufu's Pyramid, Pyramid of Khufu, and Pyramid of Cheops) is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now Cairo, Egypt, and is the only one of the Seven Wonders of the Ancient World that survives substantially intact.
Identified as the world's oldest intact ship and has been described as "a masterpiece of woodcraft" that could sail today if put into water. One of the barges found was inscribed with Khufu's name.
The Great Pyramid of Khufu is largest pyramid ever built and incorporates about 2.3 million limestone blocks and granite stones, weighing between 2.5 to 15 tons each. The construction of the pyramid demonstrates some puzzling questions about its placement and alignment. The Pyramid lies in the exact centre of gravity of the continents. It also lies in the exact centre of all the land area of the world, dividing the earths land mass into approximately equal quarters.
The Great Pyramid is located on a unique point on the Earth. Its north-south axis aligned along a meridian 31 degrees east of Greenwich. This meridian has the largest total landmass of any other meridian. Even more surprising is the east-west parallel (30 degrees north), which is also has the longest land parallel. Is this coincidence, or did the Egyptians possess a previously unheard of knowledge into the whole world?
The Pyramid is built upon a giant platform over 54,000 square metres that is constructed from limestone blocks, and in an official survey by the Egyptian Government, it was found that it was less than half an inch from being perfectly level. The sides are at almost perfect right angles and the difference in length between the longest (756.08 ft) and shortest edge (755.43 ft) is 7 inches. This represents an incredible degree of accuracy in the design and construction plans of the Pyramid, this level of accuracy only recently achievable in the modern world.
One of the largest mysteries surrounding the Pyramids is the method to their construction. Estimates vary on the size of the workforce required, somewhere between 30,000 and 300,000 and recent evidence has shown that the vast majority of workers were paid. This would indicate highly developed accounting system and hierarchical organization. Other sources show that the workforce was made not of the slave labour commonly assumed with building the pyramids, but of highly skilled artisans.
How did the Egyptians transport such large blocks of stone to the top of the Pyramid, or even on top of the previous block? Various strategies have been suggested, including a long strait ramp, progressively getting longer and narrower as height increased, or zigzag ramps up one face of the pyramid, or ramps that wrap around the pyramid.
Also, consider that summer temperatures in Egypt are 95-107F. How physiologically possible would it be to do this kind of hard manual labour for more than an hour in just a loin cloth under a boiling sun at that temperature? Could any pyramid work even be carried out after 11AM? Was the pyramid constructed at night?
A more recent, controversial theory is that the blocks were "cast" in-situe using limestone concrete. In this theory proposed by Joseph Davidovits, a materials scientist, soft limestone with high kaolinite content quarried in the wadi on the south of the Giza Plateau. The limestone was then dissolved in large, Nile-fed pools until it became watery slurry. Lime and natron was mixed in. The pools were then left to evaporate, leaving behind a moist, clay-like mixture. This wet "concrete" would be carried to the construction site where it would be packed into reusable wooden moulds and in a few days would undergo a chemical reaction similar to the 'setting' of cement. Proof-of-concept tests using similar compounds were carried out at a geopolymer institute in northern France and it was found that a crew of ten, working with simple hand tools, could build a structure of fourteen, 1.3- to 4.5-ton blocks in a couple of days.
A straight line is said to have been cut in extreme and mean ratio when, as the whole line is to the greater segment, so is the greater to the less. Euclid
In mathematics and the arts, two quantities are in the golden ratio if the ratio between the sum of those quantities and the larger one is the same as the ratio between the larger one and the smaller. The golden ratio is approximately 1.6180.
Assuming that the height of the great pyramid = 146.515m, and its base = 230.363m, and using simple maths we find that half of the base is 115.182m and the "slant height" is 186.369m
Dividing the "slant height" (186.369m) by "half base" (115.182m) gives = 1.6180, which is practically equal to the golden ratio!
In 1940, a British Air Force pilot, P. Groves, was flying over the pyramid when he noticed a strange shadow on the pyramid and captured it in the now-famous photograph.
This very unusual feature of the Great Pyramid is a concavity of the core that makes the monument an eight-sided figure, rather than four-sided like every other Egyptian pyramid. This new feature of the pyramid was not observed before 1940 as it can only be seen from the air and only under certain lighting conditions. The reason behind this concavity is unknown, as is its construction.