The Great Pyramid of Giza

A Magnificent feat of Construction

The great pyramid of Giza is the oldest of the seven wonders of the ancient world and the only one to remain largely intact.

Completed about 4600 years ago and built to a height of about 146 metres it remained the tallest man made structure for about 3800 years. The pyramid was originally covered with casing stones which provided a smooth outer surface.  In AD 1300 an unusually large earthquake loosened the casing stones which were mostly removed to build mosques and fortresses in nearby Cairo. The effects of erosion and the absence of the pyramid's original capstone its present height is now 138 meters.

Here are some statistics which indicate the amazing skill and persistence of the ancient Egyptians:

• The time for construction is unknown - estimates are from 20 to 30 years
• 500 000 tonnes of mortar were used
• The mass of the pyramid is about 5.9 million tonnes
• Its volume is approximately 2.5 million cubic meters
  • Based on an estimated construction period of 20 years this would involve installing 800 tonnes of stone every day with the placement of 12 blocks each hour day and night.
• The accuracy of construction is such that:
  • The 4 sides of the base have an average error of only 58mm in length
  • The base is horizontal and flat to within 21mm
  • The sides of the base are aligned to the 4 points of the compass to within 4 minutes of arc. The alignment is to true North, not magnetic North.
  • The finished base was squared to an average error of 2 seconds of arc
  • The ratio of the perimeter to height measured in the ancient Egyptian's unit of measure, the cubit, equals 2pi to an accuracy of less than 0.05% leading historians to believe that, although being unable to define pi, they used could it.
  • The pyramid consists of about 2.3 million limestone blocks most of which were obtained from nearby quarries.
  • Parts of the pyramid are constructed from large granite stones weighing between 25 to 80 tonnes. Approximately 8000 tonnes of granite was used - all of it from Aswan some 800 kms away from Giza and transported there by water.

Egyptologists estimate that a work force of about 200 000 was employed for the construction of the pyramid. The workers were housed in a specially designed and constructed town nearby complete with all necessary services such as bakers, schools etc.

There is a school of thought that holds that the construction of the pyramid was so huge an undertaking that it could not have been accomplished without the direct intervention of aliens!

Bruce Lyle | Membership Services Manager