This video was made possible by Assassin’s
Creed Origins, which is out today. When we think of ancient Egypt, most imagine
sand swept plains with giant pyramids jousting up from a barren desert, juxtaposed next to
the lush meandering Nile spilling nutrients to into the surrounding floodplains to feed
this burgeoning empire. But all we have for reference for this vision
of the past are the ancient monuments and artifacts that remain and ancient hieroglyphs,
that puzzled linguists for centuries. The ways of this ancient world is shrouded
in mystery, so when I was invited out by Ubisoft to get a private tour of the British Museum,
speak with historians and get hands on experience with their 3D explorable vision of ancient
Egypt in Assassin's Creed Origins to learn more, I jumped at the opportunity. Today we are going to explore this ancient
world and try to uncover one it’s greatest secrets, how a civilisation without power
machinery managed to build those gigantic godly structure. In our modern world, these structures may
seem to some as just huge piles of rock. With modern machinery, like cranes, it may
be easy to take for granted the monumental task of moving and lifting this much material. So let’s put this problem in context to
understand why it has baffled historians for centuries. The largest of the Great Pyramids, Pyramid
Khufu, was the tallest man made structure on earth for almost four thousands years. Pyramid Khufu contains over 2.3 million limestone
blocks, each weighing an average of 2.5 tonnes, which form the interior structure of the pyramid
and an additional 200,000 blocks were used for the smooth white stone casing, which now
only exists on the upper cap. but the Pyramids aren’t simply giant piles
of limestone arranged nicely, Pyramid Khufu, incredibly, contains massive interior chambers,
like the king’s chamber, which is supported by massive granite beams, with the heaviest
weighing about 40 tonnes, that’s about the same as the maximum allowable weight of a
fully laden articulated truck. These stones are located between 43 metres
and 65 metres up the pyramid. Just transporting the massive stones to the
site from the quarries was a massive undertaking, but other civilisations that predate the Egyptians
have achieved similar feats, like stonehenge, or the even more ancient Irish building of
Newgrange. The limestone for the Pyramids was quarried
nearby, much of it quarried directly next to the pyramids, while the granite was likely
taken from Aswan and transported to the site on boats. We know from hieroglyphs that the egyptians
used wooden sleds to transport heavy objects, while workers lubricated it’s movement with
water. This was simply a problem of manpower, which
the wealthy Egyptian empire was not short on. What has fascinated me is the logistic challenge
of building a structure like this, the sequence of events and mechanisms that these ancient
engineers used to lift these immense weights into place are a mystery, a mystery that many
have tried to solve, but many theories come up short. To solve this riddle, let’s start with what
we do know. First things first, unless the Pyramids were
truly built by aliens with anti-gravity machines, the pyramids were built from the bottom. Next, because of the precise geometric shape
of the pyramids, with each side of the Great Pyramid being 230.3 metres long, with the
largest difference in lengths, between the Northern and Southern edge, at only 4.4 centimetres. This level of accuracy could only have been
possible if the external casing stones were laid first, allowing any deviations to be
caught early and corrected, before the internal structure was filled in. This makes any theories for external ramps
or cranes unlikely, as they would have been extremely difficult to attach to the smooth
external wall, which was inclined at 52 degrees. Instead, the most prevalent theory suggests
a ramp on one side of the pyramid that would raise with pyramid, but this has it’s limit. When pulling a weight like this uphill, the
force required is given by this equation. The average mass of blocks was 2.5 tonnes,
or about 24,500 Newton's, there were heavier blocks, but these were mainly used in the
lower levels. Let’s set our slope angle alpha, at 7 degrees,
and the coefficient of friction between two pieces of wet wood is about 0.1, using these
figures we can calculate the force needed to pull this weight uphill at 5418 Newtons. Modern safety guidelines say the maximum any
worker should pull is 225 Newtons [1], but since this is a prolonged track and stopping
is not an option, most calculate the max each worker would pull at 150 Newtons or about
15.3 kg. So that means we would need around 36 workers
would be needed to haul this weight. This figure is reasonable, but for every additional
degree of slope at least an extra 3 workers will be needed, which would soon become extremely
impractical. The other option, of simply elongating the
ramp and maintaining the angle is completely unfeasible, as constructing the ramp would
be bigger project than the great pyramid itself. Like any modern construction project, these
are all logistical issues the Egyptians would have had to overcome. This is the core of engineering. Trying to solve problems with the tools at
hand, and now we have to reverse engineer this problem without knowing exactly what
tools the Egyptians had. One of the most convincing theories I have
seen, from French architect, Jean-Pierre Houdin, may hold the truth of the Pyramids construction. Jean-Pierre theorised that this external ramp
was used to construct up to the height of the King's Chamber at around 43 metres, allowing
the heaviest granite stones used to be hauled up this ramp. Granite has often been used in grand historic
buildings for it’s superior compressive strength, allowing the buildings to grow in
size, here the granite was tasked with supporting the immense weight of the pyramid above the
King’s Chamber. At this height the majority of the volume
of the pyramid is completed, but we still need a way of transporting those final blocks
into place. This is where the innovative part of Jean-Pierre’s
theory comes in. He proposes that while the first 43 metres
was being constructed, the workers also built an internal ramp, which would transport material
recycled from the exterior ramp to the top of the pyramid. Now this theory should be easy to prove, the
interior ramp should still exist, but the Pyramid is a protected structure, we can’t
just take it apart to see what’s inside. But we do have tools that can peer into the
internal structure without damaging it, one team used microgravimetry in 1986 to measure
the density of different sections of the pyramid. This research produced this image image, showing
a strange pattern where the green indicates lower density, which closely matches the pattern
of Jean Piere’s predicted internal ramp. I believe this is the most convincing theory
to date, but it is yet to be confirmed or disproven. The mystery of the pyramids construction may
remain a mystery forever, but you can explore this mysterious world in Assassin’s Creed
Origins, which is out today. I fell in love with the Assassin’s Creed
franchise when I got to explore Florence in Assassin’s Creed 2. It gave me a unique insight into this distant
world, and I got the exact same feeling exploring Egypt in Assassin’s Creed Origins. They are even including a mode called Discovery
Tour to turn off the hippo violence, and give you guided tours around this beautiful recreation
of the past. I really enjoyed the game, if it sounds like
something you are into, check it out with the link in the description. As always, thanks for watching and thank you
to my Patreon Supporters for helping to make this channel possible. If you want to see more content from Real
Engineering, the links to my social media accounts are in the description. I just gave a sneak peek for next weeks video
on Instagram, so if you are interested check that out.
