♪ ♪ ELLA AL-SHAMAHI: Humans.

From hunter-gatherers to builders of mega-cities in just a few thousand years.

How did this happen?

Our story so far, if it teaches us anything, it's that none of this was a foregone conclusion.

To get here, we had to harness nature at a scale we had never known before.

This place is stunning, and yet a complete and utter death trap.

And as we started to lay down roots... Wow.

...we faced new challenges.

(slide projector clicks) In some houses, there are up to 62 people buried in them.

(slide projector clicks) AL-SHAMAHI: Each generation building on the last.

Sharing ideas, inspiring, and collaborating.

It is so hard to stand here and not have goosebumps.

We learned to communicate in new ways... This is the birthplace of the alphabet.

...and built marvels.

So, this is a snapshot in time of the building of the Great Pyramid.

And you found it.

"Human: Building Empires."

Right now, on "NOVA."

♪ ♪ (birds chirping) AL-SHAMAHI: Around 300,000 years ago... ...our species, Homo sapiens, evolved in Africa.

For generations, small bands of hunter-gatherers explored the planet.

Learning to survive.

♪ ♪ Many other species of human walked the Earth alongside us.

But one by one, they disappeared... ♪ ♪ ...until only we remained.

For most of our history, our population was tiny and fragile.

Every aspect of our lives determined by the natural world.

And yet... ...everything would change.

Today, there are about eight billion of us, most of us living in cities like this one, able to connect in an instant with people across the planet.

And you might think it was inevitable, the result of progress over time.

But surely our story so far, if it teaches us anything, it's that none of this was a foregone conclusion.

♪ ♪ So how did we get here?

How did humanity transform from scattered groups of nomads into our modern, interconnected world?

What happened in that final chapter of our story that took us on a path to this place?

♪ ♪ ♪ ♪ On a remote hilltop in the southeast of Turkey... ...stands a prehistoric monument steeped in mystery.

♪ ♪ It is so hard to stand here and not have goosebumps.

This is the oldest temple unearthed anywhere on this planet.

It was built 11,500 years ago by hunter-gatherers.

That's 6,000 years earlier than Stonehenge.

And yet, somehow, our ancestors were capable of making this.

This is Göbekli Tepe.

♪ ♪ Incredible T-shaped pillars, which you could imagine would have been holding up a huge roof.

And then if we look at them, they're covered in these engravings.

So, this is a fox.

There's vultures here.

There's bear, there's wild boar.

And here... This one just has to be my favorite.

Look at these incredible teeth.

And it's hunting one of those wild boars.

And yet, this incredible feat of architecture is not the most revolutionary thing about this place.

Göbekli Tepe is not simply a temple.

It is a marker of a species in the midst of change.

Similar sites have been found across the region.

♪ ♪ In many ways, these prehistoric builders lived as their ancestors had for thousands of years.

Their days spent foraging and hunting to feed their families.

(boar squeals, falls) ♪ ♪ But they'd made one fundamental change.

After thousands of generations spent as nomads, following the herds they hunted... ...at places like Göbekli Tepe, they began to settle down.

The evidence lies not in the temple itself... ...but in the rubble surrounding it.

Now, this might not look like much compared to that, but this small square building is actually the remains of one of the first permanent houses ever built.

That there is a storage vessel, this is a grinding stone for wild wheat, and this floor of plaster and stone, this was somebody's home.

♪ ♪ This is one of the first villages.

Archaeologists think maybe a few hundred people were living here.

And calling it home.

For 300,000 years, Homo sapiens roamed freely.

But now they were gathering together to put down roots.

And so, the question is, why?

And why now?

♪ ♪ (birds chirping) (buzzing) This was a world of plenty.

Warm and abundant.

But the planet had not always been this way.

Only a few thousand years earlier, Homo sapiens were on the move... ...contending with the brutal peak of the last ice age.

Now that the climate had stabilized, food could remain abundant in a single place for longer.

And so, people started to stay.

And when large groups came together to trade and share their bounty, a feature of our brain had an opportunity to flourish like never before.

♪ ♪ Our almost limitless capacity to learn.

♪ ♪ An ability with roots that can be traced way back, right to the beginning of the human story.

(slide projector clicks) As the distant ancestors of our species were gradually evolving... (slide projector clicks) ...they were developing larger brains.

(slide projector clicks) But as their brains grew, the way they were organized was evolving, too.

(slide projector clicks) Becoming increasingly adaptable, and more able to change in response to stimulation from the outside world.

(slide projector clicks) Until they became us.

A species with a highly flexible mind.

♪ ♪ We call this flexibility neuroplasticity because it's like our brains are plastic.

They adapt, they alter, and they change.

It has some profound effects.

♪ ♪ (fire crackling, kids laughing) ♪ ♪ AL-SHAMAHI: With such a high level of neuroplasticity, Homo sapiens' skill at learning from each other makes for expert collaboration.

♪ ♪ At places like Göbekli Tepe, they gathered together to trade, feast, and share ideas.

And they carved these ideas into the stones.

The odd thing about being human is that we are constantly surrounded by a bunch of things that are so all-encompassing, and yet we never really think about where they started or where they come from.

I'm talking here about culture.

♪ ♪ Ritual, custom, language, art-- stories and ideas that have been passed down orally through generations and have now found physical form.

Places like Göbekli Tepe became so rich in meaning.

(child laughing) AL-SHAMAHI: And culture flourished.

♪ ♪ Cooperating and building connections... ...are what our brains are actually set up to do.

(slide projector clicks) Wherever humans settled down, an explosion in creativity followed.

(slide projector clicks) Launching an era of extraordinary innovation.

(slide projector clicks) We can see the results of this shift in the archaeological record.

(slide projector clicking) Which begins to seethe with the debris of new technology.

(slide projector clicks) But one innovation from around this time would have consequences greater than the settlers could possibly have imagined.

(lamb bleats) They were now no longer tracking seasonal herds, but seeking safe, reliable ways to feed themselves.

(goat bleats) They'd stopped chasing their food and started rearing it... ...providing a regular supply of milk, cheese, and yogurt.

And later, textiles, like wool.

Season after season.

(slide projector clicking) The farming of animals marked a watershed moment.

The result of this I don't think could have been predicted.

This altered relationship that they had with animals altered them, because not long after they learnt how to do this, something fascinating happened.

(fire crackling, baby cooing) Their population started to boom.

We're not really sure why this happened, but one compelling theory is that people staying in one place and not moving as much, but also having more food, having more calories, basically led to mums having more energy for reproduction.

♪ ♪ As our numbers rose, settlements began springing up.

Scattered across an area we now call the Fertile Crescent.

(rooster crows) As their populations grew, villages transformed into towns.

♪ ♪ (slide projector clicks) ♪ ♪ (slide projector clicks) And one particularly large settlement was Çatalhöyük.

♪ ♪ A strange forerunner of the towns and cities we know today.

Wow.

Every single one of these is a house?

That's right.

And you have to imagine of course, that each of these houses is a box with, with a roof.

But, uh, there's no space, really, between them, like a beehive.

The fact that they're all tightly up against each other means that the whole thing is much more structurally sound.

AL-SHAMAHI: There's literally no gap.

The only way you can get in the house is to move along the roofs and go down through a hole into the house because there's no streets.

♪ ♪ AL-SHAMAHI: Each dwelling was small and had its door in the ceiling.

The inhabitants lived much of their lives up on the roofs.

Grinding grain, trading, and feasting in the bright sunlight above their homes.

And these farmers left behind intriguing signs that they were here to stay.

What are those holes over there?

These are the ancestors who are buried beneath the floors.

In some houses, there are up to 62 people buried in them.

AL-SHAMAHI: I mean, Ian, 60-odd people being buried, that's a graveyard in a home.

We've dug up hundreds of burials here.

And what's fascinating is that people were sleeping just a few centimeters from the bones of their ancestors.

(slide projector clicks) ♪ ♪ (slide projector clicks) ♪ ♪ AL-SHAMAHI: Between the dead, the living, and their animals, this thriving town was densely packed.

At its height, some people think there were 8,000 people living at Çatalhöyük, so that's one of the largest settlements on the planet at this point.

And yet, the formula for success that was playing out here also turned out to be a bit of a disaster.

(goat bleating) Our pioneering farmer ancestors couldn't have known it, but they had opened Pandora's box.

(slide projector clicks) Amongst the many burials of Çatalhöyük... (slide projector clicks) ...were skull after skull with clear signs of violent impact.

♪ ♪ And it's something not only seen at Çatalhöyük.

(slide projector clicks) (slide projector clicking) In many early farming settlements, we start to see the unmistakable signs of violence.

(slide projector clicks) Suggesting the two might be connected.

♪ ♪ Choosing to live like this, in such close proximity with your neighbors, with the animals which you're breeding, with your rubbish, in a way that has never been seen before, leads to this cascade.

The densely populated towns had become exposed to new dangers.

Living with their animals spread disease.

Their dependence on crops made them vulnerable to failed harvests.

(people shouting) AL-SHAMAHI: And with ever-growing competition for the land near the settlement, people were not only trying to battle nature, they were battling each other.

♪ ♪ These challenges prevented towns from growing into great metropolises.

Instead, growth was followed by collapse and often exodus.

And as the early town dwellers left their homes and farms in droves, they faced a choice.

To settle down again or rejoin the vast majority of humans across the globe still living nomadic lives.

♪ ♪ For me, this is one of the biggest mysteries in the history of our species.

Because for the very first settlers, it was a disaster.

They were facing disease and famine.

And yet, at the very same time, across the planet, hunter-gatherers were thriving.

And that way of life we know works, because today, millions of people live like that.

They have made it to the 21st century just like the rest of us.

And yet we know how this story ends.

Most of us live in huge cities like this.

♪ ♪ ♪ ♪ So, what set us on a path to where we are now?

Clues can be found along the great rivers of the ancient world.

♪ ♪ There are bits of our story where geography just does not feel like a fluke.

Where, if it was gonna happen, it was always gonna happen here, and that's how you feel on the Nile as an archaeologist.

Because five-and-a-half thousand years ago, if you wanted to build something permanent and you were in Egypt or Mesopotamia, which is mostly in modern-day Iraq, the only real place to do it was along the Nile or the Tigris and Euphrates.

♪ ♪ Because beyond the thin strips of green that cut through this arid landscape, there is very little but sand and death.

♪ ♪ This narrow strip of habitable land was one of the few places to grow food and raise animals.

But to produce enough, they had to control this natural resource.

The people needed to direct the water on to their fields and harvest en masse once a year.

And so, they had no choice but to live and work together.

♪ ♪ The people flooded into the Nile Valley, jostling for space.

(people talking in background) ♪ ♪ AL-SHAMAHI: But now, instead of abandoning their communities when the towns became overcrowded... (people talking in background) ...they restructured them.

♪ ♪ When you live in a small group, you've all got to be good, or at least competent, at everything to survive.

But living in a larger group, you can suddenly specialize.

Some of you might become really good at a particular kind of textile-making.

Others might become stone makers, butchers, bakers.

Probably not candlestick makers, yet.

All cogs in a huge machine at a scale that had never been seen before.

♪ ♪ The people of these busy settlements were becoming part of a social group... ♪ ♪ ...with hundreds or thousands of strangers.

And in the process, laying the foundation for something brand-new.

♪ ♪ (birds chirping) Now, I know archaeologists are constantly pointing at walls and trying to convince people of how important they are, but this wall, this absolutely huge wall, is pretty much all that's left of the original city of Abydos.

Abydos was one of the very first cities in Egypt, and walls that look like this would have surrounded the city, indicating a momentous shift in the way humans live together.

Because to be on this side of the wall meant protection and access to the grain stores.

But to be on that side of the wall meant to literally be without.

Now, humans have always been tribal.

We've always been able to act and think as part of a group.

But what places like this prove is that tribalism was scalable to the size of a city.

♪ ♪ All along the great rivers of the ancient world... (slide projector clicks) ...huge cities began to appear as our ancestors found the secret to living at scale.

♪ ♪ (slide projector clicks) A change which would propel us forward at an astonishing rate.

(people talking in background) AL-SHAMAHI: The cities thrived.

♪ ♪ Their newly specialized populations invented, made, and traded an unprecedented number of objects.

(people talking in background) And in the process, created a tool, unassuming at first glance, that would become a powerful instrument.

I know they don't look like much.

They look like just square pieces of bone.

They were found in Abydos, in a tomb thought to be that of a king known as the Scorpion King from about 5,300 years ago.

Now, some of these symbols are very recognizable.

That's obviously a bird.

This is a plant of some kind.

And notice the holes in them.

These are effectively labels or tags.

And these symbols perhaps represented the provenance where the item that they were attached to came from.

Perhaps they have a quantity, as well, attached to them.

And then, someone had this absolutely revolutionary idea.

What if they strung them together?

♪ ♪ With some local knowledge to give them a shared meaning, gradually, the rows of images became more complex.

Until we stopped labeling and started writing.

Detailed knowledge and culture that had previously been passed down, generation to generation to generation, was now able to be preserved in a completely different way.

And the thing with writing is that, like so many of the giant leaps forward that we have made as a species-- and I, I'm thinking here about the invention of agriculture, and metalworks, and the wheel-- writing does seem like an idea whose time had come.

Because it doesn't just happen in Egypt.

♪ ♪ Again and again across the Earth, we invented forms of writing.

♪ ♪ Giving our facts, stories, and ideas lasting form.

(people talking in background) AL-SHAMAHI: And we still have no conclusive evidence as to how, or even whether, these events influenced each other or whether they happened organically, as a result of needing to keep track of things at that scale.

But however it happened, once writing was a thing, once it was out there in the world, then nothing would be the same ever again.

♪ ♪ Now laws, customs, and beliefs could be recorded permanently in ink.

But with over 700 symbols, this technology required years of study to master.

And so was the sole preserve of those trained to use it-- scribes working for the ruling class.

And the ability to send out detailed instructions to people across the land gave the rulers enormous power to influence, instruct, and build.

(slide projector clicking) In 2013, a team of archaeologists were excavating a cave on the Red Sea coast... (slide projector clicks) ...when they found ancient fragments of inscribed papyrus.

(slide projector clicks) Preserved there for over 4,000 years... (slide projector clicks) ...they're believed to be the oldest ever found... ♪ ♪ ...and a time capsule from the reign of an iconic ruler.

So, this is... This is your actual excavation notebook from the time?

PIERRE TALLET: Yeah, yeah-- every day, I was recording the papyri, and we were surprised to find most of them have the name of a king, and this pharaoh is Khufu, the builder of the Great Pyramid.

(slide projector clicks) AL-SHAMAHI: Khufu ruled Egypt for over two decades, and one of humankind's most iconic constructions was built to honor him: the first of the pyramids of Giza.

The team discovered around 1,000 pieces of papyrus, revealing a vastly complex construction project.

Wow.

Yeah.

It belongs to a kind of elites at that time, because we don't think that more than one percent of the population was able to read and write.

It's a logbook, and for example here, on the first day of the month, they are sending a boat to Heliopolis to fetch the food for the workers.

And when it arrives, it's written in red, because it's much more important for them than everything else.

About 40 days, you have a precise record of what, what he is doing.

Egyptian extracted fine limestone blocks that were used to, for the building of the outer casing of the pyramids.

So, this is... This is telling us how they built... Mm.

...the pyramids, basically.

Yeah, this is, this... This, this is the administration behind it all.

This is, yeah.

That, that's absolutely incredible.

So, this is a snapshot in time of the building of the Great Pyramid.

Mm.

And you found it.

♪ ♪ Without all those records, I think the pyramid would not have been possible.

♪ ♪ AL-SHAMAHI: You can't really overstate the significance of finding a document like that.

One from such a pivotal moment in history.

And when you read the translation, you definitely do get a sense of what a logistical feat it was, building these things.

But you do also get a real sense of how mundane and bureaucratic it all was, just kind of ordinary humans doing ordinary human things.

Between the invention of writing and the building of the pyramids, there were no major technological advancements that we know of in Egypt.

And so, for 4,500 years, people have looked at these and just had their breath taken away, and wondered how on Earth were they built.

And perhaps the answer is just this simple: writing built the pyramids.

♪ ♪ And even though they were originally built for the elites, they actually became symbols of national identity, which bind huge groups of people together on an unconscious level.

♪ ♪ The unit of human cooperation had grown from tribe to village to town to city... ...and now to nation.

♪ ♪ But alongside the emergence of these nation states was a more sinister development at a new scale.

(slide projector clicking) What had once been tribal skirmishes became state warfare... (slide projector clicking) ...recorded by the victors in art and writing.

(slide projector clicks) The emerging superpowers began launching military campaigns against their neighbors for land, resources, and manpower.

♪ ♪ Many of the early civilizations follow this pattern of growth, innovation, writing, and an ever more stratified society.

By 4,000 years ago, we'd clearly made some massive strides to the modern world, with the rise of the civilizations that were supporting so many more people, and about 70 million of us walking this planet.

But.

The disparity in the human condition had never been so wide.

Some people were living gods, and they would go on to build monuments like these to themselves for centuries.

But many more were slaves, who were forced to live in the shadows of the splendor that they'd helped to create.

And humankind's powerful new tool, writing, still remained in the hands of just a tiny number.

If we were going to get to the future, the here and now, as you and I know it, it was going to require a spark from somewhere else.

♪ ♪ Almost 4,000 years ago, a small group made a journey to one of the most inhospitable places on Earth... ♪ ♪ ...through the baking, barren waste of the Sinai Desert.

But here, in this desolate landscape, they would change the world.

♪ ♪ This place is stunning, and yet a complete and utter death trap.

It was of very little interest to the Egyptian elites.

That is, until someone found something in these mountains.

Lots and lots of copper.

And this stuff, turquoise.

(slide projector clicking) Raw materials that could be transformed into jewels and ornaments of great value.

(slide projector clicks) (slide projector clicks) If you could extract them from this harsh landscape.

Far to the north was the tiny land of Retjenu.

When Egypt demanded laborers for this treacherous mining mission, it was the unfortunate people of this small state who had no choice but to answer the call.

♪ ♪ I can't imagine what it would have been like to be dragged here to work in the turquoise mines.

In the blazing heat, in the middle of nowhere.

It must have been like being dropped onto the surface of a different planet.

♪ ♪ And even the Egyptians probably wondered if they would make it back home.

♪ ♪ The Egyptians turned to their gods for protection.

And here, high up on a desolate plateau, far from home, they built a temple to ask for it.

Remnants have survived remarkably unscathed for almost 4,000 years.

Frozen in time by the bone-dry desert.

This temple is dedicated to the goddess Hathor, who is the goddess of turquoise and miners.

And they were documenting and celebrating their presence and worshipping their gods.

And each one of these pillars represents one of the missions.

And they are hierarchical, so, you've got the pharaoh at the top, and it goes through the ranks.

You've got stonemasons, et cetera, et cetera, et cetera, until, this is the brother of the prince of Retjenu.

Retjenu is where the miners came from.

And yet the miners are so lowly that they're not even named on the pillars.

But they would have come through here.

They would've seen this grandeur, this splendor.

One theory is, the miners saw these hieroglyphs and also wanted to immortalize their presence here.

But there was a problem.

They weren't part of the elites, and so they couldn't write.

♪ ♪ It's thought the miners did what we humans have always done.

They copied what they'd seen and made it their own.

♪ ♪ This is one of the turquoise mines.

And if you look all over the walls, there are these scratches from where the workers' pickaxes have been.

But here, something else is going on.

There are about 30 or 40 of them all over this place.

Some of these have been copied from hieroglyphics, but some are completely new.

And here's how the system works.

You take the symbol and you say the name, but you only take the first sound, and you discard the rest.

So, for example, this here, this is an ox.

You can see the horns and the head here.

To the miners, this would be aleph.

Now, aleph, just take the first sound, "ah," discard the rest.

This is another symbol, this is the symbol for house.

To them, it would be bet.

So, you just take the "beh" sound at the beginning.

And if you put these two together, you start understanding what you're actually looking at here.

This is the birthplace of the alphabet.

This new script was simpler to learn than hieroglyphics because the alphabet did not represent complete words, but spoken sounds.

It was able to convey any thought with only 20 to 30 symbols.

These miners are the ones who gave birth to this, and their legacy is still with us today and is so important.

♪ ♪ In the centuries and millennia that followed... ...nearly all the early written languages fell into obscurity as those civilizations waned.

But this alphabet would only grow, spreading across the planet, reshaping and branching into many different forms.

(slide projector clicking) It now forms the basis of most known written languages... ♪ ♪ ...allowing millions, and then billions, of ordinary humans to access knowledge, to communicate, and to document their thoughts, and their existence, in every corner of the globe.

For me, this is one of the most powerful moments in the human story, because unbeknownst to the underdog, they had changed the world.

One of civilization's most profound and revolutionary ideas didn't come from an educated elite.

It came from inside these dark and miserable mines, through the copying and innovating of lowly migrant workers.

♪ ♪ (traffic humming in distance, horns honking) ♪ ♪ The invention of writing marks an ending and a beginning.

♪ ♪ Because prehistory-- so, the period before writing-- we could only really piece together using fragments and artifacts.

And now recorded time, history, had begun.

And what we see is that as writing spreads, the pace of human innovation accelerates.

♪ ♪ Because that is the power of being able to document and lay down knowledge.

(bird squawking) ♪ ♪ Generation after generation building on the last, retaining and accumulating knowledge.

Stone became bronze.

Iron became silicon.

Handwritten became printed.

Printed became typed.

And gradually, we built the future.

This is the very final bone of our series.

This is actually one of the three ear bones.

And just like every human bone we've encountered, whether Homo sapiens or otherwise, it represents a person.

This individual had a family, parents, perhaps children, friends.

But what's particularly remarkable is how much we now know about these ancient ancestors of ours, thanks to modern temples of knowledge, like this one.

The scientists here are able to extract DNA from an individual who, in this case, lived about 1,600 years ago, from a piece of bone that is so tiny, delicate, and precious.

And they're able to ask questions, like whether industrialization and agriculture actually affected our DNA, whether we're still evolving.

And to think that our knowledge has got to the point where we're even able to entertain such huge questions from something so tiny.

For me, there's a poetry in that.

♪ ♪ We can look back on when nature and luck were on our side and when they weren't.

Where we made the right decisions and where we went wrong.

But what underpins our story and makes it unique is far more than just our will to survive.

It's our cultural drive to come together, to learn from and inspire each other, to go further than what has gone before.

We are the very last species of human to walk this Earth.

And the most fascinating thing about our 300,000-year-long story is that we have no idea how much is left.

Is this basically the whole of our story, or are we on the first act or even prologue, with a long future ahead of us?

We have no idea.

But we are one species with one future.

Now, you could never have predicted how we got here.

And where we go next is up to all of us.

♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪