How Were the Egyptian Pyramids Built?
By Owen Jarus, Live Science Contributor
The pyramids of Giza
were built using techniques that took centuries to develop.
No cameras were around thousands of years ago when the
ancient Egyptians built the three pyramids of Giza, for each of three pharaohs
Khufu, Khafre and Menkaure.
And so scientists have had to piece
together clues as to how these towering monuments were constructed.
Over the past two decades, a series of new discoveries and
studies allowed researchers to paint a clearer picture of those feats.
Giza pyramids
The
first, and largest, pyramid at Giza was built by the pharaoh Khufu (reign
started around 2551 B.C.).
His pyramid, which today stands 455 feet (138 meters)
tall, is known as the "Great Pyramid" and was considered to be a
wonder of the world by ancient writers.
The pyramid of Khafre (reign started
around 2520 B.C.) was only slightly smaller than Khufu's but stood on higher
ground.
Many scholars believe that the Sphinx monument, which lies
near Khafre's pyramid, was built by Khafre, and that the face of the Sphinx was
modeled after him.
The third pharaoh to build a pyramid at Giza was Menkaure
(reign started around 2490 B.C.), who opted for a smaller pyramid that stood
215 feet (65 m) high.
Over the past two decades,
researchers have made a number of discoveries related to the pyramids,
including a town built near the pyramid of Menkaure, a study showing how water
can make blocks easier to move and a papyrus found by the Red Sea.
These have allowed researchers to gain a better
understanding of how the Giza pyramids were built.
The new finds add to older knowledge gained over the last
two centuries.
Developing pyramid-building techniques
The
techniques used to build the Giza pyramids were developed over a period of
centuries, with all of the problems and setbacks that any modern-day scientist
or engineer would face.
Pyramids originated from simple
rectangular "mastaba" tombs that were being constructed in Egypt over
5,000 years ago, according to finds made by archaeologist Sir Flinders Petrie.
A major advance occurred during the reign of the pharaoh
Djoser (reign started around 2630 B.C).
His mastaba tomb at Saqqara started off as a simple
rectangular tomb before being developed into a six-layered step pyramid with
underground tunnels and chambers.
Another leap in pyramid-building
techniques came during the reign of the pharaoh Snefru (reign started around
2575 B.C.) who built at least three pyramids.
Rather than constructing step pyramids, Snefru's
architects developed methods to design smooth-faced, true pyramids.
It appears that Snefru's architects
ran into trouble.
One of the pyramids he constructed at the site of Dahshur
is known today as the "bent pyramid" because the angle of the pyramid
changes partway up, giving the structure a bent appearance. Scholars generally
regard the bent angle as being the result of a design flaw.
Snefru's architects would correct the
flaw; a second pyramid at Dahshur, known today as the "red pyramid" —
so named after the color of its stones — has a constant angle, making it a true
pyramid.
Snefru's son, Khufu, would use the
lessons from his father and earlier predecessors to construct the "Great
Pyramid," the largest pyramid in the world.
Planning the pyramids
The
pharaohs appointed a high-ranking official to oversee pyramid construction.
In 2010, a team of archaeologists discovered papyri dating
to the reign of Khufu at the site of Wadi al-on the Red Sea.
Text on the papyri stated that in the 27th year of Khufu's
reign, the pharaoh's half-brother, Ankhaf, was the vizier (highest official to
serve the king in ancient Egypt) and "chief for all the works of the
king," archaeologists Pierre Tallet and Gregory Marouard wrote in the
journal Near Eastern Archaeology.
While the papyri said that Ankhaf was
in charge during the pharaoh's 27th year, many scholars believe it's possible
that another person, possibly the vizier Hemiunu, was in charge of pyramid
building during the earlier part of Khufu's reign.
Researchers are working to understand
the sophisticated planning that would have been involved in pyramid building,
which required constructing not just the pyramids, but also the temples, boat
pits and cemeteries located near the enormous structures.
Researchers have noted that the
Egyptians had the ability to align structures to true north very precisely,
something that may have helped in planning the pyramids.
Glen Dash, an engineer who studies the pyramids at Giza as
part of Ancient Egypt Research Associates (AERA), noted that Khufu's pyramid is
aligned to true north within one-tenth of a degree.
How the ancient Egyptians did this is not fully clear.
In a report published recently in an AERA newsletter,
Dash wrote that a circumpolar star like Polaris and lines of rope were likely
used as part of the method.
Supplies
and food
Over the past few years
archaeologists with AERA have been excavating and studying a port at Giza that
would have been used to bring in supplies, food and people.
The papyri found at Wadi al-Jarf allude to the importance
of Giza's ports, saying that limestone blocks, used in the outer casing of the
pyramid, were shipped from quarries to the pyramid sites within a few days
using boat transport.
The port that AERA archaeologists
found is located by a town built near Menkaure's pyramid.
This town had sizable homes for high officials, a barracks
complex that likely held troops and buildings where large numbers of clay
seals (used in record keeping) were found.
The ordinary workers likely slept in simple dwellings near
the pyramid site.
Estimates given by various
archaeologists for the size of the workforce at Giza tend to hover around
10,000 people for all three pyramids. These people were well-fed; in a study
published in 2013, Richard Redding, the chief research officer at AERA,
and colleagues found that enough cattle, sheep and goats were slaughtered every
day to produce 4,000 pounds of meat, on average, to feed the pyramid builders.
The finding was detailed in the book "Proceedings of
the 10th Meeting of the ICAZ Working Group 'Archaeozoology of Southwest Asia
and Adjacent Areas'" (Peeters Publishing, 2013).
Redding used the animal bone remains found at Giza, and
the nutritional requirements for a person doing hard labor, to make the
discovery.
Redding also found that animals were
brought in from sites on the Nile Delta and kept in a corral until they were
slaughtered and fed to the workers.
The
workers' meat-rich diet may have been an inducement for people to work on the
pyramids, Redding said. "They
probably got a much better diet than they got in their village,"
Redding told Live Science in 2013.
Quarrying the blocks
Many
of the stones used in Khufu's pyramid are from a horseshoe-shaped quarry
located just south of the pyramid, said Mark Lehner, an Egyptologist who leads
AERA, and engineer David Goodman.
They published their finds back in 1985 in the journal
Mitteilungen des Deutschen Archäologischen Instituts.
Construction workers would have used
blocks from a quarry located south-southeast of Menkaure's pyramid to build
that pyramid, the researchers said.
However, it is unclear which quarry was used for Khafre's
pyramid.
When nearly complete, each of the
Giza pyramids was furnished with a smooth outer casing made of limestone.
Little of this outer casing remains today, having been
reused for other building projects in Egypt over the millennia.
The papyri found at Wadi al-Jarf said
that the limestone used in the casing is from a quarry located at Turah, near
modern-day Cairo, and was shipped to Giza by boat along the Nile River and
a series of canals.
One boat trip took four days, the papyri said.
Moving the blocks
To
move the stones overland, the Egyptians would have used large sledges that
could be pushed or pulled by gangs of workers.
The sand in front of the sledge was likely dampened with
water, something that reduced friction, making it easier to move the sledge, a
team of physicists from the University of Amsterdam found in a study published
in 2014 in the journal Physical Review Letters.
"It turns out that wetting
Egyptian desert sand can reduce the friction by quite a bit, which implies you
need only half of the people to pull a sledge on wet sand, compared to dry
sand," Daniel Bonn, a physics professor at
the University of Amsterdam and lead author of that study, told Live Science in
2014.
The scientists said scenes in ancient Egyptian artwork
show water being poured in front of sledges.
Most Egyptologists agree that when
the stones arrived at the pyramids, a system of ramps was used to haul the
stones up.
However, Egyptologists are uncertain how these ramps were
designed. Little evidence of the ramps survives, but several hypothetical
designs have been proposed over the last few decades.
New data may come from the Scan
Pyramids Mission, an initiative being undertaken by researchers at three
different universities, the Heritage Innovation Preservation Institute and the
Egyptian Ministry of Antiquities.
This project's scientists are in the process of scanning
and reconstructing the Giza pyramids using a variety of technologies.
In addition to finding out more about the construction of
the pyramids, the project may also reveal if there are any undiscovered
chambers within the structures.
Owen Jarus writes about archaeology and
all things about humans' past for Live Science. Owen has a bachelor of arts
degree from the University of Toronto and a journalism degree from Ryerson
University. He enjoys reading about new research and is always looking for a
new historical tale.
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