It has a lifespan of around 20 years. We may never know exactly how the pyramid was built, but we can estimate how many people were needed to complete it. We must begin with a time limit of about 20 years, which is the length of the reign of Khufu, the pharaoh who commissioned the building (he died around 2530 B.C.E.).
The pyramid itself is about 250 feet on each side, making it one of the biggest buildings in history. Its height exceeds that of any temple or monument found in Egypt and it would have been visible for hundreds of miles in every direction. Even now, it is visible for hundreds of miles in every direction. The largest pyramid ever built was by Khufu's grandson, King Chephren. It is believed that only four such pyramids might have been built because the labor force needed to build them must have been extremely large. However, two more were later added to the site by other Pharaohs.
In order to construct the pyramid, stones had to be dragged from far away sites and transported over great distances. In addition, wood was used to build scaffolding so workers could reach high places where blocks of stone were placed by others. It is estimated that there are 1.5 million pieces of stone used in its construction. Finally, men worked tirelessly to expose the rock beneath the surface so more stone could be brought in.
This task would have taken many years.
The Great Pyramid was completed around 2650 B.C.E., so its construction began some time after this.
The original estimate for the height of the pyramid was based on the number of stones that were used to build it. The builders probably brought the stone from different locations and worked on them at their convenience, so different parts of the monument may have been ready at different times. In fact, excavations in 1920-21 by Victor Loret discovered five levels with sealed chambers inside the pyramid, indicating that it might have been built over several periods of time.
In total, the pyramid consists of 2 million limestone blocks and is therefore one of the largest buildings in history. It takes about 21,000 tons of salt water to wash away all the soil that has been added to the pyramids over time.
The king's burial chamber is the last space you would expect to find air conditioning. However, recent research shows that ancient Egyptians also enjoyed cooling off in the summer months by opening window holes throughout the palace walls to allow in some fresh air.
While the pyramid was initially built by 4,000 men over the period of 20 years using strength, sleds, and ropes, Houdin estimates that erecting the pyramid today utilizing stone-carrying trucks, cranes, and helicopters would take around five years and cost roughly $5 billion.
He says shipping all the granite required for these structures alone would be impossible. The heaviest piece of granite ever found was 16 pounds (7.3 kg), and it was only 1/8 of an inch (3 mm) thick. The average weight of a truckload of freight is about 70 tons, so even if you collected enough garbage to fill a city bus every hour, day after day, you wouldn't have enough trash to weigh 70 tons.
The pyramid itself is about the same height as the Washington Monument, which stands at 555 feet (169 m). It's estimated that there are 2.6 million stones used in its construction. If each one were as heavy as the one we found, the pyramid would not be possible to move even if you employed a workforce of 10,000 people with pneumatic tools who work eight hours a day for two months straight without a break.