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00:03The Great Pyramid, a monument built four and a half thousand years ago.
00:10The last surviving wonder of the ancient world.
00:14The ancient Egyptians took what they had and used it ingeniously.
00:18They couldn't have done it any better.
00:20For centuries, the Great Pyramid has been a symbol of mystery, a structure with no equal.
00:26This is an experiment and this is a one-off deal.
00:30How did ancient Egyptians create this vast edifice and why did they build it?
00:38The only way to solve these mysteries is to blow this colossal monument apart,
00:46dive deep inside it and stone by stone unearth the astonishing secrets hidden within this ancient wonder.
01:08On the outskirts of the Egyptian city of Cairo tower the ancient pyramids of Giza.
01:19Built by a civilization renowned for their expertise in architecture and astronomy.
01:26An ancient people with bizarre death rituals who built lavish tombs for their dead.
01:32And on this Giza plateau, the biggest tomb of all, is the Great Pyramid.
01:40This extraordinary monument is the legacy of the Pharaoh Khufu.
01:46It remained the tallest structure on earth for more than three and a half thousand years.
01:53Today, teams of archaeologists and scientists are using new techniques in the hope of unlocking its secrets.
02:01But how do you make sense of a monument so immense?
02:08A structure made from over two million solid stone blocks.
02:14Assembled with breathtaking precision.
02:17Many weighing more than a car.
02:22A building with narrow, mysterious tunnels leading to two massive chambers.
02:30Designed to withstand huge weights from above.
02:36The ultimate resting place for a Pharaoh's body.
02:41How and why did the ancients build this six million ton Goliath in the sands of the Egyptian desert?
02:53Archaeologist Mark Lehner has been studying this monument for over 40 years.
03:00Mark knows that when the Pharaoh Khufu ordered engineers to build the largest pyramid ever.
03:05He set the ultimate deadline.
03:08They had to finish before the death of the king.
03:12The engineer had his life and reputation on the line in order to complete the pyramid within the king's lifetime.
03:21It was long thought that Khufu ruled for 23 years.
03:25Recently, new findings of dates suggest Khufu might have reigned maybe 30 some years, maybe 35.
03:32So that gives him a little more leeway.
03:34Having said that, it is a very audacious act.
03:38That implies supreme confidence that within the allotted time, fate has given your lifetime, you will reach the pinnacle.
03:49Khufu had set the challenge and the deadline.
03:53The big mystery is how did builders ensure that the massive monument would be complete in time?
04:00To solve this riddle, experts need to work out exactly how it was built.
04:05Yeah, right here.
04:09The Egyptians left clues everywhere how they built the pyramids.
04:12We just have to figure out what the clues mean.
04:15Glenn Dash is searching for tiny clues that previous investigations may have missed.
04:22His work is part of the most detailed mapping of the Great Pyramids base ever undertaken.
04:28The first task today is to map the first line of building stones on here, the west side of the
04:32pyramid.
04:34Glenn is trying to figure out how the ancient builders chiseled out the massive limestone blocks.
04:41Here you've got a sweep of chisel marks that are on the side.
04:47You can see that the guy had the hammer went chw chw chw chw chw chw chw smoked it wrong.
04:51It went to the next layer went chw chw chw chw chw chw.
04:54The limestone is a good building material to use.
04:57It's hard.
04:58It has great compressive strength.
05:00But it still can be cut and shaped to whatever shape he happens to do need.
05:04The pyramid builders didn't have to look far to find limestone.
05:09It's the bedrock under the Giza Plateau.
05:12But how long would it have taken to chisel out all of the blocks so finely?
05:26Quarrying expert Adele Kaleni and a team of master stonemasons are trying to answer this question.
05:33They need to square off a limestone block to restore a wall near the pyramid.
05:38We would like to cut some blocks actually and change it from the rough shapes which come from modern quarry
05:45like this.
05:46To show how it's different between the old and modern techniques.
05:52First, they must split a rough limestone block in half using modern steel tools.
05:58If they split the stone in wrong way, that will destroy the block.
06:05Striking the rock in the right place should make it crack.
06:12Oops.
06:18The rock is split, but it's tough going for the tools.
06:23Adele thinks that the builders of the pyramid needed whole teams of tool repairers to keep the work on track.
06:32Another team is just repairing the tools each time.
06:35And that's quite important for keeping the work going in the, you know, faster way.
06:42The pyramid builders didn't have hard steel.
06:45They used softer copper tools which needed frequent sharpening.
06:52Seeing how hard it is to square off a block with modern tools highlights the challenges.
06:59One block is, I mean, it takes one hour and a half from the workmen today.
07:04That's really quite a time to split one block.
07:08But if you go to, or you come to the grid permit with two million blocks, especially the large blocks
07:14at the bottom, that takes a lot of time.
07:17Experts think it might have taken five workers up to a half day to square off and shape each block
07:22so it fitted perfectly next to another.
07:27Making every single block in the pyramid this accurate in the time they had seems impossible.
07:34So how did the Egyptians do it?
07:39Mark Lehner believes the pyramid builders found a shortcut to speed up construction.
07:46Obviously they could do really well squared blocks.
07:50I think it would have been well nigh impossible to build the whole pyramid with regular, squared, nicely fitted blocks.
08:00Higher up on the pyramid, the outer stones have fallen away.
08:05Mark explores them to reveal a clue.
08:08The blocks inside the pyramid look very different from those that make up the outside.
08:14Higher up in the pyramid and deeper in, look at this joint between two stones.
08:20Now it's a good six inches to eight inches wide and just stuffed with big globs of mortar and smaller
08:27limestone pieces.
08:31Mark thinks that the pyramid builders used this technique deliberately.
08:40To meet their deadline, they had to cut and lay more than 200 blocks a day.
08:46Which is why they cheated.
08:49They cut the blocks on the outside with precision so you could barely fit a hair in between them.
08:56But just a few layers further in, things change.
09:00Here the blocks are much less accurate with big gaps between them.
09:06Putting quick and dirty blocks on the inside and pretty ones on the outside saved the Egyptians many millions of
09:14man hours.
09:16The key to building the pyramid as fast as humanly possible.
09:25Shaping blocks for construction was just the start of the pyramid builders challenge.
09:31Now they had to move them.
09:35Archeologists think that ancient Egyptians hauled stones using wooden sledges and rope.
09:40But the big riddle is how they could drag tons of stone and sledge all the way up the pyramid.
09:49Just 230 feet from the pyramid, Mark Lehner has found evidence that points to a solution.
09:56So here, just off the southwest corner of the Khufu pyramid, we have the foundations of a ramp that still
10:02remains.
10:02That the Egyptians used to make this large stone tomb.
10:07Dragging a large block up a shallow ramp like this doesn't seem like a problem.
10:13But then turn your imagination to a straight on ramp that sloped all the way up to the top of
10:20the great pyramid of Khufu.
10:23Could ancient builders have used ramps to reach such heights?
10:30A ramp would work well for the lower levels.
10:34But as the pyramid rises, the slope gets too steep.
10:41To keep the ramp shallow, it would have to be over a half mile long and need as much building
10:48material as the pyramid itself.
10:51So one theory is that the Egyptians used a shallow ramp until two-thirds of all blocks were in the
10:58base.
11:01Then they built a narrow spiral ramp up around the edge of the pyramid to lift blocks all the way
11:07to the top without making their ramp too steep.
11:12How do you build a ramp?
11:14This ancient ramp shows us.
11:16You build two retaining walls of larger stones and then infill with the material that must have been everywhere at
11:22Giza.
11:23Debris of stone cutting and quarrying.
11:26Limestone debris and even sand and gravel of the desert.
11:33Cutting and moving the pyramid's building stones took both ingenuity and brute force.
11:41Now, new evidence reveals why it was so important for builders to make this pyramid in the first place.
11:56The ancient Egyptian pharaoh Khufu constructed the Great Pyramid with one goal in mind.
12:03He wanted an impenetrable tomb to protect his body when he died.
12:10Scientists are revealing why this was so important at the Grand Egyptian Museum Conservation Center.
12:23Dr. Medhat Abdallah heads up the wood conservation laboratory.
12:29Today, Dr. Abdallah is set to examine a sarcophagus.
12:33A 2,600-year-old ancient coffin found south of Giza.
12:39He hopes it will shed light on why preserving the dead was so important for the ancient Egyptians.
12:46So we are going to remove the lead.
12:51The team wants to check on the condition of the mummy hidden inside.
13:11This is Lenin, and this is very fragile in ancient Egypt.
13:17They invented the mummification as a method for keeping their bodies safe without the dead.
13:24Without any deterioration.
13:28Ancient Egyptians thought that for the soul, known as the Ba, to live on after death, it must be able
13:34to recognize the dead body.
13:37They mummify this body to keep all the features of the dead person so the spirit would identify him and
13:45come to his dead body again.
13:49Dr. Abdallah is sure that the Great Pyramid was the ultimate vault in which to keep the pharaoh's body safe.
13:57So the Great Pyramid is all about keeping or preserving the body.
14:06Traditionally, ancient Egyptians buried mummies in deep chambers they carved into the ground underneath structures like the pyramids.
14:15But the pharaoh Khufu wanted something different.
14:18For the very first time in history, the burial chambers would be above ground, inside the pyramid, at its core.
14:30Deep inside the limestone blocks is the heart and soul of the Great Pyramid.
14:40A warren of tunnels and air shafts that lead to the so-called Queen's Chamber.
14:48Above it, a huge gallery three stories tall leads to a much bigger chamber with a 16-foot wide ceiling.
14:58The pharaoh's tomb.
15:00These chambers faced a real danger of collapse from the force of millions of tons of stone blocks piled all
15:07around them.
15:14Inside the Great Pyramid, archaeologist Mark Lehner hunts for clues as to how engineers protected the burial chambers from collapse.
15:23He needs to crawl through over 160 feet of tight passageways to reach the first chamber, the Grand Gallery.
15:32For me, this is the most impressive place in the pyramid, the Grand Gallery.
15:38Suddenly you go from 1.2 meters to more than 8 meters in height.
15:44There's no other space like it in the entire history of architecture.
15:50The stone blocks that form the wall here are limestone fitted together with superfine precision.
15:58You can see they never smoothed the walls of the Grand Gallery.
16:02So you can still see the marks of the individual worker.
16:05You can see the worker's hand.
16:07And you can see where they're coming in with a little chisel about the width of your pinky finger
16:11to very carefully dress the stone at the corners where the seams match so that they don't break.
16:19And, oops, they did break a little bit there.
16:24Some 65 feet above, Mark reaches the King's Chamber.
16:30He thinks that this is the final resting place for the mummified pharaoh.
16:35Well, the whole pyramid was about this place and this sarcophagus.
16:40When you turn and come to the west end of the King's Chamber and find here the sarcophagus,
16:47you're right on the center axis of the pyramid.
16:50It's too big to get into the entrance of the King's Chamber.
16:53Therefore, they had to put it into the chamber when the chamber was still open to the sky.
17:00The Egyptians needed to ensure that this chamber remained intact,
17:04even as they built the rest of the pyramid on top of it.
17:08It's the first time that they created a space this wide and this high up inside a pyramid,
17:16more than five meters.
17:18They were clearly very worried about structural failure.
17:23They wanted to avoid the irony that the very pyramid that was supposed to protect the King's body
17:31would be the force that would collapse and crush it.
17:37How did ancient Egyptians design a chamber to protect the mummified pharaoh?
17:52Ancient Egyptians needed to ensure their mummified pharaoh remained intact inside the pyramids.
17:58But did engineers know how to build a protective chamber?
18:01If they had built the chambers like simple cavities, the weight of the pyramid above would have crushed them.
18:07So they topped the Queen's Chamber with huge slabs that formed a strong angled room
18:12to divert the pressure sideways into the blocks around it.
18:16For the Grand Gallery, they assembled the blocks in a primitive arch-like structure,
18:21forming an extremely tall and stable vault.
18:25And for the King's Chamber, they pulled out all the stops.
18:29Five gigantic granite stress-relieving chambers and a gabled roof above.
18:38This intervening stack of stress-relieving chambers is totally unique.
18:44They're making it up as they go along.
18:48The radical roof was not the only special feature the pyramid's engineers used to protect the King.
18:55Instead of limestone, they used red granite.
18:58This hard rock gave an elegant finish and was much stronger.
19:03So granite is much harder than limestone.
19:06They shaped these blocks with dolerite hammers, dolerite being a stone as hard as granite.
19:13They literally pounded them into shape and then sanded the fine surfaces,
19:18including those fine joints, with sand and clay.
19:25Shaping red granite took more than a hundred times longer than limestone.
19:30But that was easy compared to the challenge of transporting it.
19:34This stone comes from quarries nearly 600 miles away.
19:40How did the ancient Egyptians transport massive blocks right across their kingdom?
19:51There's a clue hidden at the foot of the Great Pyramid.
19:57Under limestone slabs, archaeologists have made a startling discovery.
20:03A deep pit filled with pieces of ancient Lebanese cedar wood.
20:09Some look like simple planks.
20:11Others have more elaborate shapes.
20:15What are these ancient bits of wood and what are they doing under the pyramid?
20:23Scientists think they are part of a sacred contraption buried alongside the pharaoh.
20:30Designed to help him in the afterlife.
20:36At the nearby conservation center,
20:39Director of Restoration Esa Zeden heads up a team that stores the wooden pieces as they come out of the
20:45pit.
20:47This is a storm of organic artifacts.
20:49This is a storm controlled by humidity and temperature.
20:53Esa keeps the ancient wooden pieces safely locked and wrapped up.
20:57He was the first person to touch them since the ancient Egyptians.
21:034,600 years.
21:05Very, very, very long time.
21:08I can't believe that I am the man who touched it for the first time.
21:13Esa hopes this find will be as spectacular as similar pieces found in a neighboring pit over 60 years ago.
21:22In a museum built directly over that earlier pit,
21:25craftsmen have assembled the wooden pieces.
21:30They form a boat.
21:32Buried alongside the pharaoh Khufu.
21:37A vessel designed to transport the king in the afterlife.
21:44This is the first boat of King Khufu.
21:47It was founded in Powhat 1,224 pieces, including the ore.
21:56Restorers took almost 20 years to carefully preserve and then rebuild this ancient vessel.
22:02It was in very good conditions and the wood is very, very strong.
22:10Archaeologists discovered that this boat has a very special design.
22:14A design that helped the pyramid builders transport goods far and wide.
22:24Khufu's royal boat comes in neatly laid out pieces.
22:29It's an ancient Egyptian flat pack design.
22:33The pieces have holes so you can tie them together into a ship that you can easily take apart and
22:39rebuild.
22:45Archaeologists think that similar flat pack boats were carried overland in pieces to the Red Sea.
22:50To be assembled so they could ship in copper from the Sinai.
22:55And on the Nile they carried seriously heavy cargo.
23:00Precious building blocks for the Great Pyramid.
23:08Boats turned Egypt's River Nile into a super highway for construction materials and supplies.
23:16Builders could transport the red granite of the king's chamber nearly 600 miles in less than a month.
23:24Now that the Egyptians had access to the material they needed to build a super-sized pyramid, they had a
23:29new problem.
23:30How to make all this flawless for their god-king?
23:43At Egypt's Great Pyramid, Glenn Dash leads a mapping team trying to unlock the monument's engineering secrets.
23:53This one is going to be right here, don't worry about getting on the bedrock.
23:58He uses a total station.
24:01A device which bounces a laser beam off a reflector to record the exact positions of blocks at the base
24:07of the pyramid.
24:09You can just put the rod there in the corner.
24:12They shoot from the total station, relay the point number, shoot a point, we move to the next corner.
24:19Shoot a point, you have to make sure that the rod is vertical, has a little bubble here.
24:25By taking such precise measurements, Glenn can investigate the extraordinary precision with which the pyramid builders worked.
24:32The more that you research it, the more you realize how remarkable they were.
24:36I mean, they built this entire building. The only tools they had were wood, rope, copper and stone.
24:41So the ancient Egyptians, what they did was they took what they had and used it ingeniously.
24:47They couldn't have done it any better.
24:50The mapping team has revealed that the precision of the pyramid's ancient builders was out of this world.
24:58The base of the pyramid is nearly perfectly square.
25:00The corners are nearly perfect right angles. They're perfect to within 1 20th of 1 degree.
25:06If you take a look at a compass that you would use for mapping or for hiking, take a look
25:11at what 1 degree looks like and imagine 1 20th of that.
25:14You see just how fine of an angle that is.
25:17So why did the ancient Egyptians go to so much effort to make the perfect pyramid?
25:29With over 2 million blocks, there's a lot that can go wrong.
25:34If the pyramid's faces weren't each at exactly the same angle, the apex would lean to one side.
25:45If the corners weren't precisely at right angles, the pyramid would squash.
25:51And if the layers went out of line, you'd get one very twisted pyramid.
25:58Ape had to be perfect.
26:01This way, the builders could finish the pyramid off with a flawless layer of gleaming white limestone casing stones.
26:15Today, there's hardly any trace of the white casing stones.
26:19What's left is the framework of backing stones that sat beneath them.
26:24On the north side of the pyramid, archaeologist Mark Lehner is investigating what the casing stones looked like.
26:32It's only here on the north side that we actually get a sample of the finished state of the pyramid.
26:40And the finest joinery of all.
26:42Here we have some of the casing blocks still remaining.
26:46And they're massive here at the bottom.
26:50They weigh from 15 to 17 tons.
26:53Over the years, people have stolen almost all of the high-quality casing stones for construction elsewhere.
27:01When the whole pyramid was covered with these white casing blocks, it must have been dazzling, blinding almost.
27:08It must have been a real beacon in the sunlight, like today.
27:13These casing stones would only fit if the backing stones formed a perfect pyramid.
27:21But the Great Pyramid's scale was unprecedented.
27:24So how did ancient engineers learn the skills they needed?
27:30Archaeologists are unearthing clues 12 miles to the south.
27:37This is Saqqara, home to Egypt's first pyramid.
27:43The Step Pyramid of the Pharaoh Djoser.
27:48This pyramid is a prototype.
27:50It's where the ancient Egyptians first learned the art of pyramid building.
27:55We are going to climb out 64 meters.
27:59Are you ready for that?
28:01Engineer Yasser Gadot oversees restoration work on this ancient monument.
28:07The Step Pyramid is 100 years older than the Great Pyramid.
28:12And in places, it's beginning to collapse.
28:15We are lifting up limestone.
28:17We are lifting around 30 to 35 pieces per day just to repair the pyramids.
28:26Workers are replacing old weathered limestone blocks with new ones.
28:32This is a new restoration and this is an old block.
28:37So, to keep these original stones as we can see it on this area,
28:43we have to re-put these new stones just to stabilize it.
28:51Yasser's conservation work here helps experts to study how ancient Egyptians built this pyramid
28:56and what gave them the idea for the shape.
29:06Dr. Mustafa El Hamraoui is an engineer who's tried to decode this pyramid prototype.
29:13It's the first ever superstructure that has been built in masonry.
29:18It's the beginning of the evolution towards the perfect pyramid.
29:25He sees evidence that this pyramid started like a mastaba,
29:29a simple rectangular structure that covers a tomb.
29:34From this view, you can clearly see the line of the first mastaba here.
29:40So, it was meant to be only this mastaba at first.
29:45But it turned out not to be quite feasible from the Nile Valley.
29:51The first single mastaba was too low.
29:55So, the engineer built a series of mastabas on top, each slightly smaller than the last.
30:02Now the tomb was visible from all around.
30:07This pyramid wasn't meant to have a smooth skin of casing stones.
30:12So, the steps didn't have to be perfect and plans could change.
30:19But imperfection was a luxury the builders of the Great Pyramid could not afford.
30:24They would have to plan ahead.
30:32In Giza, Glenn and the mapping team search for clues that could prove ancient engineers planned for perfection by first
30:40plotting out a perfect square.
30:43This one capped with mortar on the side, ancient mortar.
30:47Do you know that's an ancient cap?
30:49Distinctively square one here.
30:51They think that these carved holes in the bedrock are the key to the pyramid precision.
30:56So, this fellow here is going to be 2656.
31:07They've mapped over a thousand holes so far.
31:10What we have here is evidence of what we think is the very earliest stages of construction at the pyramids.
31:17It's capped now, but originally it was a hole.
31:23The theory is that ancient Egyptians dug holes at intervals.
31:28Put in wooden posts and join them with road to mark a straight line.
31:36Then they used simple tools to create a 90 degree angle so they could stake out a perfect corner.
31:45This way they marked out the square base and then paved the edges with perfectly leveled limestone slabs.
31:57Now, when they put down each layer of blocks, they could line up the corners and sides to create the
32:04perfect pyramid.
32:06This was the crucial first step in laying out the Great Pyramid.
32:10It's coming up with a square, relatively accurate square, which guided everything else.
32:15It was the reference for everything else that followed.
32:18With the pyramid side square, builders could set the casing stones safe in the knowledge they could fit.
32:26Everything about the Great Pyramid shows great perfection.
32:29Right down to the direction it faces.
32:34Glenn thinks engineers used the movement of the sun to align the sides to the exact points of the compass.
32:42In the end, the Great Pyramid's almost flawless shape may have been just as important spiritually as structurally.
32:49What we do know spiritually is that they thought it was a resurrection machine.
32:54It was very important to them.
32:55And in order to ensure that they would be able to resurrect the spirit of the dead king, I think
33:02they thought they had to make the perfect pyramid.
33:06The ancient Egyptians had built the perfect monument for their pharaoh and his precious possessions.
33:13But how could they protect the king's body and treasures from tomb raiders?
33:28The Great Pyramid.
33:30A titanic tomb built for the pharaoh Khufu four and a half thousand years ago.
33:38Its purpose was to preserve the king for all eternity.
33:42A supersized safe for his mummified body and treasures.
33:47At the conservation labs at the Grand Egyptian Museum, Dr. Madat Abdallah wants to understand the importance of treasures in
33:56ancient Egyptian tombs.
33:58Most of artifacts come from ancient Egypt, workers for the afterlife and keeping them in the tombs.
34:08These grave treasures would be a great reward for any tomb robber daring enough to break in.
34:15So embalmers decorated mummies with prayers to keep them safe.
34:19That is the god, the god of justice in ancient Egypt.
34:22And that is a prayer, religious praise, word for keeping and preserving and saving the dead person.
34:32At the Great Pyramid, archaeologist Mark Lehner is checking out a clue that suggests that the pharaoh relied on more
34:39than prayers and curses to ward off robbers.
34:43This is a small room just outside the king's chamber.
34:47Here Khufu's builders designed a line of defense against anyone who would enter the king's chamber had they got this
34:56far.
34:56These grooves and protrusions are not decorative.
35:02They are part of a very primitive machine.
35:13Solid walls, some 260 feet thick, surround the chambers, leaving the passageways as the weak link.
35:23So at the king's chamber, workers carved out a set of grooves just outside the entrance and fitted three massive
35:31granite slabs, which workers would drop down once the king's mummy was safely inside.
35:38To block the entrance to the passageways below, they fitted three even bigger granite blocks to cut off access to
35:46the inner sanctum.
35:48Then they completely concealed the entrance under a seamless layer of limestone.
35:57The builders hoped that these three layers of defense would keep robbers out.
36:02Outside the king's chamber, the granite slabs are missing today.
36:06But Mark finds grooves which once held ropes to lower the blocks.
36:12So the ropes came up and down through these semicircular grooves.
36:16The portcullis slabs slid down through these panels.
36:19So the whole thing was like a primitive machine that the builders who closed the pyramid could put into action
36:29from the other side after they got out.
36:33The solid granite plugs that seal off the mouth of the ascending passageway are still in place today.
36:41So what you're looking at here is the butt end of the first granite plug in the bottom of the
36:47ascending passage.
36:48Originally, the Egyptians put a log across here, stuck into these sockets that they cut into the sidewalls.
36:56So the builders hoped that this would prevent anyone from getting up to the upper chambers, especially the king's chamber.
37:04Unfortunately for the king, these formidable defenses weren't enough.
37:10No mummy or treasures have ever been found in the Great Pyramid.
37:15So robbers must have broken in.
37:18The mystery is how.
37:25Outside the Great Pyramid, archaeologists Mark Lehner and Glenn Dash are joining forces to uncover how the raiders would have
37:31carried out a heist here.
37:32So Glenn, if you're going to get into the pyramid when it was complete, and you want to get in
37:38from the original entrance, this is it.
37:41The casing stones that once hit this entrance are long gone, and today a metal grill secures it.
37:48It's really interesting coming up here because you can see some of the tremendous engineering that is probably hidden elsewhere
37:55in the pyramid.
37:58Builders made the main entrance small, but they support its roof with giant angled limestone slabs.
38:06Is this where robbers broke in?
38:09They wouldn't have known about any of this because presumably the casing was all intact, and the entrance was camouflaged,
38:16and they would have no idea of all this massive basement.
38:17Even if they pulled the casing away, they're going to find this massive stone, and they're going to say, let's
38:21do it someplace else.
38:22I do like the idea, now that I think of it, that part of the overbuilding was just to deter
38:28people who were poking around here.
38:30They would have had to hit that descending passageway right on to know it was there, otherwise they were going
38:36up against these massive stones.
38:38The pyramid builders' effort to hide and perhaps fortify this entrance seems to have worked, because robbers instead began tunneling
38:47in from a little lower down.
38:50So the story goes that they started on the center axis of the pyramid, thinking that's where the passages would
38:57be.
38:58And they heated the rock, the limestone, and then poured cold water or even vinegar, the story goes, to crack
39:06it, and gradually forced their way into the pyramid along this tunnel.
39:15Only 32 feet below the concealed entrance, the raiders broke through the casing stone and started tunneling.
39:24After carving through almost 100 feet of limestone blocks, they hit the first granite blocking slabs and dug around them
39:34to reach the ascending passage.
39:37Then they had a clean run to the king's chamber, only to face the final hurdle, the second set of
39:45granite slabs ancient Egyptians had dropped in years before.
39:50As far as we can tell, they broke through the barrier to reach the jackpot.
39:58Mark thinks that the accuracy of the robbers' tunnel is almost too good to be just a lucky break.
40:06It always seemed to me that somebody, whoever made this tunnel, knew exactly where to turn to get around the
40:14blocks, the granite plugging blocks that blocked the way from the descending passage up the ascending passage and to the
40:22chambers.
40:23Whoever did this almost knew where to turn.
40:29Mark and Glenn suspect that raiders struck not long after Pharaoh Khufu's death, and that it could have been an
40:36inside job.
40:38One of the open questions is how much of those people that had tunneled in through the entrance passage that
40:45people use now, how much did they know before they started tunneling of what the internal structure of the pyramid
40:50was?
40:51Well, that's why I suspect, but I'm not sure, that whoever did the forced passage knew where to go.
40:56But that means somebody fairly close in time to the building, maybe his descendants, workers.
41:04Maybe the people that built it.
41:06The raiders may have cracked the defenses of the Great Pyramid, but the real treasure was impossible to steal, the
41:13building itself.
41:14The pyramid may not have fulfilled its function, ultimately, to keep the royal body safe for all time.
41:22But the measures they took to preserve the king was, in fact, their real gift to the future.
41:28That is almost more valuable for their memory than preserving the body of the king.
41:34And we're still trying to learn what it was that they were trying to tell us with all this experience.
41:37Exactly. For us, this is much more the treasure. This is much more the great discovery.
41:43And there's so much more to learn.
41:49Today, the Great Pyramid offers us an extraordinary glimpse into an ancient world.
41:55Four and a half thousand years after it was built, the most enigmatic monument on Earth is still giving up
42:02its secrets.
42:06The more experts discover, the more incredible this ancient edifice appears.
42:13The ingenious, time-saving trick of its roughly cut core.
42:19The chambers deep inside it.
42:23The mysterious burial pits with flat-packed boats.
42:27And the remarkable security devices.
42:31Come together to make the Great Pyramid.
42:35A masterpiece of ancient engineering.
42:57A masterpiece of ancient empire.
42:57And the two people who don't know the same.
42:57Even this happened in a long history.
42:57The relentless a strong plantation.
42:58The quintessential technology.
42:58The best of the!", the japanese.
42:59The third number.
42:59The fifth generation.
43:00The fifth generation.
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