Pyramids of Giza: The Great Pyramid Of Giza: How It Was Built In Less Than 7 Years
Credit: K. Cantner, AGI. The Great Pyramid, the oldest and largest of the three monuments, dominates the skyline with sides that rise an impressive meters above the plateau. Completed in about B.
The bulk of the plateau is composed of stacked carbonate layers deposited from the Late Cretaceous through the Eocene on the floor of the Tethys Sea. The remnants of this ancient ocean make up the modern Mediterranean Sea. Khufu and his successors had their pyramids built atop the Mokattam Formation, a series of relatively hard middle-Eocene limestone and dolomite layers that form the surface of this part of the plateau. Many of the blocks that compose the Great Pyramid appear to have come from the same formation, excavated in a quarry a short distance south of the structure.
The Mokattam breaks cleanly along bedding layers and is riddled with many vertical joints, so the rock was ideal for dividing into blocks, even with the simple hand tools available to Ancient Egyptian masons. The scale of the construction is mind-boggling; the Great Pyramid alone consists of an estimated 2. The majority of these consist of nummulitic limestone , which contains numerous fossil shells from especially large single-celled marine foraminifera of the genus Nummulites. The limestone blocks, after being removed from the quarry, were probably dragged overland using ropes and sleds, possibly aided by wet sand to reduce friction.
In fact, the near perfection of these ancient monuments, including their alignment with the cardinal directions, has inspired many debates. Many of the blocks in the Great Pyramid host the calcified remains of Nummulites, large single-celled marine organisms that flourished in the Tethys Sea about 50 million years ago.
After giving our eyes a chance to adjust to the dark interior, we began ascending a sloping wooden ramp that lines the floor of a narrow tunnel. It hosts a lidless, four-ton granite sarcophagus that archaeologists believe was placed there first, with the pyramid later erected around it. Unlike the rest of the monument, where limestone is so prevalent, this rectangular room is completely lined with smooth blocks of medium-gray syenite, a relative of granite that contains less silica. This darker rock, along with the dim light and sarcophagus, creates an appropriately somber mood.
Despite its antiquity, 95 percent of its wood is original. The syenite blocks, which weigh up to 50 tons apiece, were shipped down the Nile from Aswan, more than kilometers to the south. This stone, which is about million years old , is part of the Arabian-Nubian Shield, a group of Precambrian rocks sutured together during the final assembly of Gondwana, the southern supercontinent that joined with its northern counterpart to form Pangea. Before continuing our tour, we stopped just below the tourist entrance to see a casing layer of glistening limestone, one of the few remaining scraps of the higher-quality, snow-white Tura Limestone that once covered the lower-quality blocks quarried nearby.
The first precision measurements of the pyramid were made by Egyptologist Sir Flinders Petrie in —82 and published as The Pyramids and Temples of Gizeh. Many of the casing-stones and inner chamber blocks of the Great Pyramid fit together with extremely high precision. Based on measurements taken on the north-eastern casing stones, the mean opening of the joints is only 0.
The completed design dimensions, as suggested by Petrie's survey and subsequent studies, are estimated to have originally been Egyptian Royal cubits high by cubits long at each of the four sides of its base. Some Egyptologists consider this to have been the result of deliberate design proportion. They believe that the observed pyramid slope may be based on a simple seked slope choice alone, with no regard to the overall size and proportions of the finished building.
The Great Pyramid consists of an estimated 2. The Tura limestone used for the casing was quarried across the river. Ancient Egyptians cut stone into rough blocks by hammering grooves into natural stone faces, inserting wooden wedges, then soaking these with water. As the water was absorbed, the wedges expanded, breaking off workable chunks.
Once the blocks were cut, they were carried by boat either up or down the Nile River to the pyramid. At completion, the Great Pyramid was surfaced with white "casing stones"—slant-faced, but flat-topped, blocks of highly polished white limestone. Visibly, all that remains is the underlying stepped core structure seen today.
Many more casing stones were removed from the great pyramids by Muhammad Ali Pasha in the early 19th century to build the upper portion of his Alabaster Mosque in Cairo, not far from Giza. These limestone casings can still be seen as parts of these structures.
Later explorers reported massive piles of rubble at the base of the pyramids left over from the continuing collapse of the casing stones, which were subsequently cleared away during continuing excavations of the site. Nevertheless, a few of the casing stones from the lowest course can be seen to this day in situ around the base of the Great Pyramid, and display the same workmanship and precision that has been reported for centuries.
He suggested a redetermination of north was made after the construction of the core, but a mistake was made, and the casing was built with a different orientation. Many alternative, often contradictory, theories have been proposed regarding the pyramid's construction techniques. The Greeks believed that slave labour was used, but modern discoveries made at nearby workers' camps associated with construction at Giza suggest that it was built instead by tens of thousands of skilled workers.
Verner posited that the labour was organized into a hierarchy , consisting of two gangs of , men, divided into five zaa or phyle of 20, men each, which may have been further divided according to the skills of the workers. One mystery of the pyramid's construction is its planning. John Romer suggests that they used the same method that had been used for earlier and later constructions, laying out parts of the plan on the ground at a 1-to-1 scale. He writes that "such a working diagram would also serve to generate the architecture of the pyramid with precision unmatched by any other means".
Without the use of pulleys, wheels, or iron tools, they used critical path analysis methods, which suggest that the Great Pyramid was completed from start to finish in approximately 10 years. From this original entrance, there is a Descending Passage 0. After There is a continuation of the horizontal passage in the south wall of the lower chamber; there is also a pit dug in the floor of the chamber.
Some Egyptologists suggest that this Lower Chamber was intended to be the original burial chamber, but Pharaoh Khufu later changed his mind and wanted it to be higher up in the pyramid. Originally concealed with a slab of stone, this is the beginning of the Ascending Passage. The Ascending Passage is The lower end of the Ascending Passage is closed by three huge blocks of granite, each about 1. One must use the Robbers' Tunnel see below to access the Ascending Passage.
At the start of the Grand Gallery on the right-hand side there is a hole cut in the wall. This is the start of a vertical shaft which follows an irregular path through the masonry of the pyramid to join the Descending Passage. The passage is 1. The "Queen's Chamber"  is exactly halfway between the north and south faces of the pyramid and measures 5. At the eastern end of the chamber there is a niche 4. The original depth of the niche was 1.
Great Pyramid of Giza
The horizontal distance was cut in by a British engineer, Waynman Dixon, who believed a shaft similar to those in the King's Chamber must also exist. He was proved right, but because the shafts are not connected to the outer faces of the pyramid or the Queen's Chamber, their purpose is unknown.
At the end of one of his shafts, Dixon discovered a ball of black diorite a type of rock and a bronze implement of unknown purpose. Both objects are currently in the British Museum. The shafts in the Queen's Chamber were explored in by the German engineer Rudolf Gantenbrink using a crawler robot he designed, Upuaut 2. Some years later the National Geographic Society created a similar robot which, in September , drilled a small hole in the southern door, only to find another door behind it.
Research continued in with the Djedi Project. Realizing the problem was that the National Geographic Society's camera was only able to see straight ahead of it, they instead used a fibre-optic " micro snake camera " that could see around corners. With this they were able to penetrate the first door of the southern shaft through the hole drilled in , and view all the sides of the small chamber behind it.
They discovered hieroglyphs written in red paint. They were also able to scrutinize the inside of the two copper "handles" embedded in the door, and they now believe them to be for decorative purposes. They also found the reverse side of the "door" to be finished and polished, which suggests that it was not put there just to block the shaft from debris, but rather for a more specific reason.
The Grand Gallery continues the slope of the Ascending Passage, but is 8. At the base it is 2. There are seven of these steps, so, at the top, the Grand Gallery is only 1. It is roofed by slabs of stone laid at a slightly steeper angle than the floor of the gallery, so that each stone fits into a slot cut in the top of the gallery like the teeth of a ratchet. The purpose was to have each block supported by the wall of the Gallery, rather than resting on the block beneath it, in order to prevent cumulative pressure. At the upper end of the Gallery on the right-hand side there is a hole near the roof that opens into a short tunnel by which access can be gained to the lowest of the Relieving Chambers.
Perring , who dug tunnels upwards using blasting powder. In the shelves there are 54 slots, 27 on each side matched by vertical and horizontal slots in the walls of the Gallery. These form a cross shape that rises out of the slot in the shelf. The purpose of these slots is not known, but the central gutter in the floor of the Gallery, which is the same width as the Ascending Passage, has led to speculation that the blocking stones were stored in the Grand Gallery and the slots held wooden beams to restrain them from sliding down the passage.
At the top of the Grand Gallery, there is a step giving onto a horizontal passage some metres long and approximately 1. Fragments of granite found by Petrie in the Descending Passage may have come from these now-vanished doors. In , scientists from the ScanPyramids project discovered a large cavity above the Grand Gallery using muon radiography , which they called the "ScanPyramids Big Void".
Its existence was confirmed by independent detection with three different technologies: nuclear emulsion films, scintillator hodoscopes , and gas detectors. The "King's Chamber"  is 20 Egyptian Royal cubits or It has a flat roof 11 cubits and 5 digits or 5. The purpose of these shafts is not clear: they appear to be aligned towards stars or areas of the northern and southern skies, yet one of them follows a dog-leg course through the masonry, indicating no intention to directly sight stars through them. They were long believed by Egyptologists to be "air shafts" for ventilation, but this idea has now been widely abandoned in favour of the shafts serving a ritualistic purpose associated with the ascension of the king's spirit to the heavens.
The King's Chamber is entirely faced with granite. Above the roof, which is formed of nine slabs of stone weighing in total about tons, are five compartments known as Relieving Chambers. The first four, like the King's Chamber, have flat roofs formed by the floor of the chamber above, but the final chamber has a pointed roof. Vyse suspected the presence of upper chambers when he found that he could push a long reed through a crack in the ceiling of the first chamber.
It is believed that the compartments were intended to safeguard the King's Chamber from the possibility of a roof collapsing under the weight of stone above the Chamber. As the chambers were not intended to be seen, they were not finished in any way and a few of the stones still retain masons' marks painted on them. One of the stones in Campbell's Chamber bears a mark, apparently the name of a work gang. The only object in the King's Chamber is a rectangular granite sarcophagus , one corner of which is broken.
BIG VOID, BIGGER QUESTIONS
The sarcophagus is slightly larger than the Ascending Passage, which indicates that it must have been placed in the Chamber before the roof was put in place. Unlike the fine masonry of the walls of the Chamber, the sarcophagus is roughly finished, with saw-marks visible in several places. This is in contrast with the finely finished and decorated sarcophagi found in other pyramids of the same period. Petrie suggested that such a sarcophagus was intended but was lost in the river on the way north from Aswan and a hurriedly made replacement was used instead.