Cities

NARRATOR: VIEWED FROM SPACE, IT'S EASY TO SEE THE IMPACT OF CIVILIZATION.

EVERY CLUSTER OF LIGHT IS ANOTHER CITY...

MILLIONS OF STRANGERS COEXISTING, COOPERATING, SHARING IDEAS.

THE CITY IS CIVILIZATION.

BUT WHY ARE WE COMPELLED TO LIVE IN SUCH LARGE GROUPS?

WHAT ARE THE ADVANTAGES OF CITY LIFE?

MAN: CITIES ACT ALMOST LIKE COLLECTIVE BRAINS, WHERE YOU HAVE ACCESS TO THE VIEWPOINTS AND TALENTS OF MILLIONS OF PEOPLE.

WOMAN: IF YOU WANT YOUR CITY TO BE SUCCESSFUL, YOU NEED PEOPLE TO BE THERE.

YOU HAVE TO GIVE THEM A PIECE OF THE PIE.

MAN 2: THESE PEOPLE WERE BURSTING WITH INGENUITY, AND THIS REALLY GOES TO SHOW HOW THE CITY IS THE ENGINE OF INVENTION.

NARRATOR: WE DIDN'T ALWAYS LIVE THIS WAY.

FOR 99% OF OUR TIME ON EARTH, HUMANS STAYED AMONG FRIENDS AND RELATIVES IN SMALL, MOBILE BANDS.

BUT THEN... WE SETTLED DOWN, GREW FOOD, WORSHIPED GODS...

FOUGHT BATTLES, WROTE STORIES, SOLD GOODS, AND BUILT CITIES.

[INDISTINCT CHATTER] NARRATOR: THIS IS THE STORY OF THAT TRANSITION, STEPPING-STONES ON THE ROAD TO CIVILIZATION.

[SHOUTS] NARRATOR: IT'S A STORY SET ACROSS THE GLOBE IN THE MIDDLE EAST, CENTRAL AMERICA, SOUTHERN ASIA... ALL OF THEM SEEDBEDS OF CIVILIZATION.

HERE, OUR ANCESTORS WROTE THE BLUEPRINT BY WHICH WE STILL LIVE OUR LIVES.

THIS IS WHERE THE MODERN WORLD BEGAN.

NARRATOR: THE WORLD'S EARLIEST CIVILIZATION EMERGED IN THE MIDDLE EAST.

IT WAS HERE, 12,000 YEARS AGO, WE STARTED ON A JOURNEY THAT WOULD LEAD TO THE CITIES OF TODAY.

THERE HAVE BEEN NO CIVILIZATIONS WITHOUT CITIES, NO CITIES WITHOUT CIVILIZATION.

AND THE SPARK WAS LIT HERE, IN SOUTHERN TURKEY, AT A PLACE CALLED GOBEKLI TEPE.

OVER THE LAST 20 YEARS, ARCHAEOLOGISTS HAVE DISCOVERED MORE THAN A HUNDRED T-SHAPED STONE PILLARS, ERECTED IN UP TO 20 CIRCLES.

THE SITE IS CURRENTLY CLOSED WHILE TURKISH AUTHORITIES BUILD A ROOF TO PROTECT IT.

BUT NEARBY, RESEARCHERS CAN EXAMINE A FULL-SIZE REPLICA, A DUPLICATE OF THE ANCIENT STRUCTURE.

ARCHAEOLOGIST JENS NOTROFF BELIEVES HE KNOWS WHY GOBEKLI TEPE WAS BUILT.

THERE ARE STRONG HINTS THAT IT WAS USED AS A GATHERING PLACE, WHERE SEVERAL GROUPS OF HUNTERS AND GATHERERS FROM THE SURROUNDING LANDSCAPES WERE MEETING THERE FOR OCCASIONAL FEASTS AND RITUALS.

[OVERLAPPING CHATTER] NOTROFF: WE'VE FOUND A LOT OF BONES, ACTUALLY, ORYX AND GAZELLE BONES, IN PARTICULAR.

AND YOU COULD IMAGINE THAT ALCOHOL PLAYED A ROLE, SO THERE ARE CERTAIN HINTS THAT EVEN BEER WAS CONSUMED AND, PERSONALLY, I DON'T SEE WHY DANCING AND MUSIC SHOULDN'T PLAY A ROLE HERE AS WELL.

[ALL CHANTING AND CLAMORING] NARRATOR: HUNDREDS OF PEOPLE WOULD MEET HERE, USUALLY IN LATE SUMMER OR EARLY FALL, AND STAY FOR A FEW WEEKS.

NOTROFF: FOR MOBILE GROUPS, IT'S VERY IMPORTANT TO REGULARLY MEET JUST TO EXCHANGE INFORMATION, MAYBE GOODS, AND MOST IMPORTANTLY, MARRIAGE PARTNERS TO KEEP THE GENE POOL OF THE GROUP FRESH.

WHAT'S DIFFERENT AT GOBEKLI TEPE IS THAT THEY SOMEHOW STARTED TO DECIDE TO MARK THESE MEETING PLACES WITH MONUMENTS, LEAVING AN IMPRESSION IN THE LANDSCAPE, BASICALLY SAYING, "WE ARE HERE."

NARRATOR: AS WELL AS BUILDING THESE GIANT PILLARS, THE PEOPLE AT GOBEKLI TEPE DECORATED THEM WITH ELABORATE CARVINGS.

NOTROFF: IF YOU THINK OF THE CAVE ART OF THE OLDEST STONE AGE-- THE FAMOUS CAVE PAINTINGS FROM FRANCE AND SPAIN, FOR EXAMPLE-- YOU IMMEDIATELY HAVE PICTURES IN YOUR MIND OF ANIMALS, A LOT OF ANIMALS.

HUMAN BEINGS ARE RARELY DEPICTED, AND IF SO, THEY ARE RATHER SMALL.

HERE AT GOBEKLI TEPE, THERE ARE STILL ANIMALS PRESENT, LIKE THIS FOX HERE, AND WHILE IT LOOKS RATHER BIG, IT DWARFS COMPARED TO THE BACKGROUND IT IS PROJECTED ONTO, AND THAT IS THE T-SHAPED PILLARS WHICH ARE SO CHARACTERISTIC FOR GOBEKLI TEPE.

AND ACTUALLY, WE CAN RECOGNIZE THESE T-SHAPED PILLARS AS ANTHROPOMORPHIC, AS HUMANLIKE BEINGS.

YOU CAN SEE THAT WE HAVE ARMS AND HANDS DEPICTED IN RELIEF, AND EVEN PIECES OF CLOTHING, LIKE A LOINCLOTH HANGING DOWN FROM A BELT.

WHAT IS IMPRESSING HERE IS THEIR SHEER MONUMENTALITY, THE SIZE OF 5.5 METERS OF THESE CENTRAL PILLARS.

I COULD IMAGINE THAT THEY MAYBE REPRESENT IMPORTANT ANCESTORS, SO THEY ARE MEANT TO DEPICT SOMETHING BIGGER, SOMETHING MORE SPECIAL, I THINK.

NARRATOR: THE FIRST STONES WERE PUT IN PLACE AT GOBEKLI TEPE ALMOST 12,000 YEARS AGO.

THE SITE IS MORE THAN TWICE AS OLD AS STONEHENGE OR THE EGYPTIAN PYRAMIDS.

[ROPES CREAKING] BUT WHY GO TO THE EFFORT OF BUILDING A MONUMENT?

NOTROFF: THE ATTRACTING FACTOR WAS THE SOCIAL ASPECT, SO PEOPLE WERE GATHERING FOR A FEAST, AND WHILE THEY WERE THERE, THEY WERE STARTING TO COOPERATIVELY CONSTRUCT THESE MONUMENTS, WHICH WERE ALSO PART OF THE SOCIAL ASPECT OF THE FEAST.

[WOMEN CHATTERING] NOTROFF: SO IT'S CONNECTED; YOU CAN'T SEPARATE IT, ACTUALLY.

IT'S ALL PART OF THE SAME EVENT.

FEASTING AND CONSTRUCTION ACTIVITY GOES HAND-IN-HAND.

NOTROFF: I THINK IT'S VERY IMPORTANT TO STRESS THAT THE COMMUNITY ASPECT OF THIS COOPERATIVE WORK IS LIKE THE GLUE PUTTING-- HOLDING TOGETHER THE WHOLE SOCIETY OF THESE HUNTER-GATHERERS.

NARRATOR: HERE, BEFORE THE EMERGENCE OF CIVILIZATION, PEOPLE WERE EXPRESSING A BASIC URGE... TO BE TOGETHER, TO BE SOCIAL.

[WOMAN SINGING IN JAPANESE] NARRATOR: THAT SAME URGE LEADS TO THE MEGA-CITIES OF TODAY.

TOKYO IS THE WORLD'S MOST POPULOUS CITY.

38 MILLION PEOPLE LIVING NEXT TO EACH OTHER, ON TOP OF EACH OTHER, SIDE BY SIDE.

JUST AS AT GOBEKLI TEPE, WE CRAVE COMPANY.

WE WANT TO BE SOCIAL.

EVOLUTIONARY PSYCHOLOGIST MICHAEL MUTHUKRISHNA BELIEVES SOCIABILITY IS AT THE HEART OF CIVILIZATION.

BEING SOCIAL IS FUN.

WE GET TO HANG OUT TOGETHER, WE TELL JOKES, WE SWAP GOSSIP, BUT BEING SOCIAL IS MUCH MORE THAN THAT.

IT'S THE PRIMARY WAY THAT WE TRANSMIT KNOWLEDGE AND INFORMATION.

THE MORE PEOPLE THAT YOU HAVE ACCESS TO, THE BETTER THE SELECTION OF IDEAS AT YOUR DISPOSAL, AND THE MORE YOU CAN RECOMBINE INTO SOMETHING BRAND-NEW.

THIS IS THE KEY TO CULTURAL EVOLUTION: SOMEONE THINKS OF SOMETHING, SOMEONE ELSE ADAPTS IT TO A BRAND-NEW ENVIRONMENT, SOMEONE INCREMENTALLY IMPROVES ON IT.

COPYING, RECOMBINING, AND LEARNING FROM EACH OTHER-- THIS IS WHAT HUMANS ARE GOOD AT, AND THIS IS THE KEY TO OUR INTELLIGENCE.

NARRATOR: THE MOST IMPORTANT REQUIREMENT OF ANY CIVILIZATION IS TO FEED ITS PEOPLE.

IT'S IMPOSSIBLE TO CREATE CITIES WITHOUT A RELIABLE SUPPLY OF FOOD.

NOTROFF: BACK IN THE PERIOD WE'RE TALKING ABOUT HERE, PEOPLE WERE MOSTLY STILL MOBILE HUNTER-GATHERERS... [OVERLAPPING CHATTER] SO WHERE THEY'RE OCCASIONALLY STAYING SEASONALLY IN THE SAME PLACE, BUT USUALLY WHERE THEY'RE ROAMING THE LANDSCAPE AND LIVING FROM WHAT NATURE ACTUALLY DELIVERED TO THEM, FOLLOWING GAME, GATHERING FOODS AND PLANTS AND NUTS AND SO ON.

NOTROFF: TO STAY LONGER AT ONE PLACE, YOU CERTAINLY HAVE TO GO A STEP FURTHER, TO NOT ONLY TAKE FROM NATURE, BUT CONTROL THE ENVIRONMENT, CREATE YOUR OWN FOOD.

NARRATOR: 20 MILES FROM GOBEKLI TEPE GROWS A TYPE OF WILD GRASS FOUND ONLY IN THIS REGION, A STRAIN OF WHEAT.

[OVERLAPPING CHATTER] NARRATOR: 10,000 YEARS AGO, HUNTER-GATHERERS HERE TOOK A GIANT LEAP.

THEY STARTED CULTIVATING THE WHEAT, SELECTING THE BEST SEEDS, PLANTING... NURTURING...

HARVESTING.

THIS IS KNOWN AS DOMESTICATION.

WHAT HAPPENS TO WHEAT ONCE YOU STARTED DOMESTICATING IT IS YOU ACTUALLY CHANGED THE PLANT.

SO YOU ARE ENCOURAGING SPECIFIC CHARACTERISTICS YOU SEE AN ADVANTAGE IN, LIKE LESS BRITTLENESS OR BIGGER SEEDS.

SO YOU'RE CREATING A NEW FORM OF THE PLANT, WHICH IS NOT ANYMORE WILD, BUT DOMESTICATED.

NOTROFF: WE ARE DISCUSSING GENE-MANIPULATED FOOD THESE DAYS AS IF IT WAS SOMETHING NEW, BUT ACTUALLY WE'RE DOING THIS SINCE THE VERY BEGINNING OF DOMESTICATION.

THE FEASTING ACTIVITY HERE AND THE NEED TO SUPPLY THESE FEASTS WITH FOOD, IN MY OPINION, TRIGGERED A NEW DEVELOPMENT WHICH SUBSEQUENTLY LED TO THE DOMESTICATION OF WHEAT, AND FINALLY TO FARMING.

[CHILDREN LAUGHING] NARRATOR: FARMING WAS THE GREATEST INVENTION OF THE ANCIENT WORLD, A CATALYST FOR CIVILIZATION, ESSENTIAL FOR CITY LIFE, AND FARMING SPREAD AROUND THE GLOBE.

WHEAT IS NOW EATEN BY 2 1/2 BILLION PEOPLE ACROSS THE WORLD... A STAPLE FOOD OF CIVILIZATION.

[BIRDS SCREECHING] FOR CITIES TO EMERGE, PEOPLE HAD TO SETTLE DOWN.

FARMING A PATCH OF LAND, YOU NEED TO TEND TO IT ON A YEAR-ROUND BASIS.

IT BECOMES HOME.

375 MILES EAST OF GOBEKLI TEPE LIES ONE OF THE OLDEST FARMING VILLAGES IN THE WORLD, ASIKLI HOYUK.

IT WAS FIRST SETTLED OVER 10,000 YEARS AGO.

THE EXCAVATIONS HERE ARE RUN BY TURKISH ARCHAEOLOGIST MIHRIBAN OZBASARAN.

[OZBASARAN SPEAKING NATIVE LANGUAGE] TRANSLATOR: WE DISCOVERED A TRANSITION FROM A MOBILE, HUNTER-GATHERER WAY OF LIFE TO AN AGRICULTURAL WAY OF LIFE, WHERE PEOPLE WERE NOW LOOKING AFTER ANIMALS AND GROWING CROPS.

NARRATOR: THIS EXCAVATED CROSS-SECTION OF THE VILLAGE HAS UNCOVERED 1,000 YEARS OF LIFE AT ASIKLI HOYUK.

AT THE BOTTOM ARE THE EARLIEST REMAINS.

OVER GENERATIONS, THE PEOPLE OF ASIKLI HOYUK BUILT ON TOP OF WHAT HAD COME BEFORE.

HERE, ARCHAEOLOGISTS DISCOVER EVIDENCE OF VERY EARLY FARMING.

[OZBASARAN SPEAKING NATIVE LANGUAGE] TRANSLATOR: AT THE HIGHER, LATER LAYERS, WE SEE A GREATER VARIETY IN THEIR DIET.

WE SEE THE BEGINNINGS OF ANIMAL DOMESTICATION, ESPECIALLY WITH SHEEP AND GOATS.

FOR INSTANCE, HERE IN THIS SECTION, WE FIND ANIMAL FECES DATING TO AROUND 8200 BC.

THIS IS CRUCIAL PROOF THAT ANIMALS WERE KEPT WITHIN THE VILLAGE, NEXT TO THE HOUSES AND FED BY HUMANS.

NARRATOR: AT ASIKLI HOYUK, PEOPLE WERE ALSO GROWING THEIR OWN PLANTS.

[OZBASARAN SPEAKING NATIVE LANGUAGE] TRANSLATOR: IN MY HAND IS AN ANCIENT GRAIN OF WHEAT.

WE KNOW THEY GREW WHEAT, AND THROUGH TIME, IT BECAME MORE COMMON, AND THEY BEGAN TO GROW A LOT MORE OF IT.

WE ARE SEEING THE SHIFT TO A FARMING WAY OF LIFE THROUGH SEEDS LIKE THIS.

[OVERLAPPING CHATTER] NARRATOR: THIS WAS NOTHING SHORT OF A REVOLUTION.

FOR THE FIRST TIME IN HUMAN HISTORY, PEOPLE HAD STOPPED MOVING AND STARTED SETTLING...

HUNDREDS OF PEOPLE IN ONE PLACE.

BEFORE VILLAGES LIKE ASIKLI HOYUK, NO ONE HAD LIVED LIKE THIS, AT THIS DENSITY, IN SUCH PERMANENT DWELLINGS.

AS THIS REPLICA OF THE VILLAGE SHOWS, THE ARCHITECTURE DEVELOPED OVER TIME FROM SUBTERRANEAN, ROUND HOUSES TO SOMETHING MORE RECOGNIZABLE.

TRANSLATOR: THESE RECTANGULAR BUILDINGS, MADE FROM MUD BLOCKS, WERE USED AS HOUSES.

TRANSLATOR: THEY WERE BUILT VERY CLOSE TO ONE ANOTHER.

AS YOU CAN SEE, THE GAPS ARE QUITE NARROW, AND LIFE WAS LIVED MOSTLY ON THE ROOF.

[OVERLAPPING CHATTER] NARRATOR: THE HOUSES HAD NO DOORS.

THEY WERE ENTERED FROM ABOVE.

TRANSLATOR: THE HOUSES HERE ARE NOT REALLY BIG.

SOME HAVE A SINGLE ROOM, OTHERS HAVE TWO ROOMS.

6 OR 7 PEOPLE WOULD LIVE HERE.

WHAT'S INTERESTING IS PEOPLE HERE BURIED THEIR DEAD IN A FETAL POSITION IN A PIT DUG UNDER THEIR FLOORS.

HAVING LAID THEM THERE, THEY'D THROW EARTH ON TOP, RE-PLASTER, AND LIFE WOULD CARRY ON AS NORMAL.

[WOMAN CRYING] TRANSLATOR: I DON'T THINK THEY WANTED TO BE SEPARATED... [CRYING CONTINUES] SO THEY COULD CARRY ON LIVING WITH THE DEAD.

NARRATOR: THERE WERE ALSO PUBLIC BUILDINGS HERE, SET APART FROM THE RESIDENTIAL AREA.

TRANSLATOR: THIS IS A PLACE WHERE PEOPLE CAME TOGETHER FOR CELEBRATIONS AND CEREMONIES FROM TIME TO TIME.

EVERYTHING WE DISCOVERED AT ASIKLI HOYUK SUGGESTS LIFE HERE WAS COLLECTIVE AND COMMUNAL.

EVERYONE WAS MORE OR LESS EQUAL.

THERE WERE NO SOCIAL OR MATERIAL DIFFERENCES; WHETHER IT WAS FOOD OR JOBS, EVERYTHING WAS SHARED.

WE KNOW THEY COOKED OUTSIDE IN ROASTING PITS AND DIVIDED UP THE FOOD, SO WE BELIEVE IT WAS AN EGALITARIAN SOCIETY.

[SHEEP BLEATING] NARRATOR: TODAY, WE TAKE THE FARMING WAY OF LIFE FOR GRANTED.

BUT FOR THE FIRST FARMERS, THE BENEFITS WERE UNCLEAR.

[CATTLE LOWING] THE NEW DIET, DEPENDENT ON WHEAT, MEANT MORE CARBOHYDRATES, LESS PROTEIN, AND FEWER VITAMINS THAN BEFORE.

ARCHAEOLOGIST BRENNA HASSETT HAS BEEN STUDYING THE SKELETONS FOUND AT ASIKLI HOYUK AND HAS UNCOVERED A CLEAR PATTERN.

HASSETT: FARMING SEEMS TO COINCIDE WITH A REVOLUTION IN VERY BAD DENTAL HYGIENE.

THE COMBINATION OF CARBOHYDRATES AND SUGAR IS THE WORST THING THAT YOU COULD POSSIBLY DO FOR YOUR TEETH.

WHAT WE'VE GOT HERE IS SOMEONE WHO'S WORN THEIR TEETH INCREDIBLY QUICKLY AND ALSO MANAGED TO GET JUST ENOUGH BACTERIA IN THERE TO REALLY START THE ROT.

THAT IS A PAINFUL CAVITY, PROBABLY; THAT ONE YOU WOULD FEEL.

NARRATOR: AS A RESULT OF THE NEW DIET, THE FIRST FARMERS GOT SHORTER.

AVERAGE HEIGHT DROPPED BY 5 INCHES, FROM 5'8" TO 5'3".

HASSETT: THE FEMUR IS THE SORT OF TOP BONE OF YOUR LEG, SO IT WOULD FIT HERE ON ME.

AND MY FEMUR, OF COURSE, GOES FROM HERE TO HERE.

THIS IS MUCH SHORTER.

THE ASIKLI HOYUK PEOPLE WOULD HAVE BEEN SHORTER THAN ME, AND I'M NOT THAT TALL.

NARRATOR: BUT IT WASN'T JUST THE FOOD THAT PUT A STRAIN ON THEIR BONES.

FARMING WAS HARD WORK, A LIFE OF TOIL IN THE FIELDS.

HASSETT: SO WHAT WE HAVE HERE ARE SEVERAL VERTEBRAE.

THIS IS IN YOUR BACK.

THIS IS SORT OF...ABOUT YEA, AND IF YOU CAN JUST IMAGINE THE HORRIBLE FEELING-- THAT TORSION YOU GET WHEN YOU LIFT SOMETHING HEAVY, AND YOU SHOULDN'T DO IT-- IMAGINE DOING THAT REPETITIVELY TO THE POINT WHERE YOUR BONES ACTUALLY GROW TOGETHER.

THAT'S NOT A VERY MOBILE BACK.

THE OTHER THING THAT WE WILL LOOK AT IS YOUR KNEE.

THIS SHOULD BE THE NICE, CLEAN SURFACE OF YOUR KNEE.

THERE SHOULD BE SOME CARTILAGE PROTECTING THE SURFACE.

WHAT YOU GET HERE IS WHERE THE CARTILAGE HAS FAILED, STOPPED PROTECTING THAT JOINT, AND THE BONE HAS STARTED TO REACT.

SO ALL OF THIS HERE, EXTRA BONY GROWTH, THAT'S ARTHRITIS.

THAT IS THE PROBABLY QUITE PAINFUL CHANGES THAT ARE HAPPENING TO THE BONE AS A RESULT OF WEAR AND TEAR.

SO YOU MIGHT THINK, HAVING GONE FROM HUNTING-GATHERING LIFESTYLE WITH ITS SORT OF FREEDOM AND ITS MOBILITY AND THE CHANCE TO SEEK RESOURCES WHEREVER, THAT, YOU KNOW, SORT OF WAKING UP ONE DAY AND FINDING YOURSELF AN ASIKLI HOYUK FARMER, YOU MIGHT LOOK AROUND AT YOUR SKINNY LEGS, ROTTING TEETH, REDUCED LIFESPAN, AND THINK THAT YOU GOT A PRETTY POOR DEAL.

[OVERLAPPING CHATTER] NARRATOR: BUT IF LIVING TOGETHER AS FARMERS WAS SO DISASTROUS, WHY DID IT CATCH ON?

WHAT WAS THE UPSIDE OF BEING A FARMER?

HASSETT: THERE IS ONE MAJOR BENEFIT TO FARMING, WHICH IS NUMBERS.

FARMERS HAVE MORE BABIES.

HUNTER-GATHERERS TEND TO SPACE THEIR BABIES FAIRLY FAR APART, ABOUT EVERY 4 YEARS, ON AVERAGE.

IF YOU ARE HIGHLY MOBILE, TRYING TO CARRY A TODDLER AND AN INFANT AT THE SAME TIME IS NOT GOING TO BE TERRIBLY EASY, WHEREAS IF YOU'RE SETTLED-- IF YOU DON'T HAVE TO KEEP A TODDLER WITHIN A SORT OF METER'S ARM'S REACH AT ALL TIMES-- YOU ACTUALLY DON'T NEED TO SPACE YOUR CHILDREN QUITE SO FAR APART.

COMPARED TO THE 4 YEARS THAT THE HUNTER-GATHERERS ARE REALLY SORT OF SPACING THEIR CHILDREN, AGRICULTURE'S--THE AVERAGE IS MORE LIKE TWO YEARS.

[OVERLAPPING CHATTER AND LAUGHTER] HASSETT: THAT'S WHY THE WORLD JUST GETS COVERED IN FARMERS, AND IT'S NO LONGER COVERED IN HUNGER-GATHERERS.

NARRATOR: AS FARMING SPREAD, COMMUNITIES GREW BIGGER.

MORE FOOD MEANT MORE PEOPLE.

VILLAGES TURNED INTO TOWNS, WHICH WOULD TURN INTO CITIES-- THE BUILDING BLOCKS OF CIVILIZATION, UNDERPINNED BY FARMING.

MAN: ♪ BOOM!

♪ ♪ BOOM!

♪ ♪ BOOM!

♪ NARRATOR: ANOTHER BENEFIT OF FARMING WAS TO CREATE A SURPLUS OF FOOD...

WHICH ALLOWED US TO REORGANIZE OUR LIVES.

MAN: ♪ YEAH ♪ NARRATOR: WHILE OTHERS PRODUCED OUR DAILY BREAD, WE COULD DO OTHER JOBS, BEING BUILDERS OR ARTISANS OR CHEFS.

RATHER THAN JACKS OF ALL TRADES, WE BECAME MASTERS OF ONE.

WE BECAME SPECIALISTS.

[WOMAN SPEAKS JAPANESE, BICYCLE BELL RINGS] IN MODERN CIVILIZATION, EVERYONE IS A SPECIALIST OF ONE KIND OR ANOTHER.

I SPECIALIZE IN THE EVOLUTIONARY SCIENCES, BUT I KNOW FAR LESS ABOUT NURSING, PLUMBING, OR PRACTICING THE LAW.

MUTHUKRISHNA: IF I WANT TO DO SOMETHING, EVEN SOMETHING RELATIVELY SIMPLE, I RELY ON A WHOLE NETWORK OF SPECIALISTS.

TAKE FOOD, FOR EXAMPLE.

FOOD USED TO BE A RELATIVELY SIMPLE THING.

WHEN WE WERE HUNTER-GATHERERS, I WOULD FORAGE FOR MY OWN FOOD, PROCESS IT IN SOME WAY, COOK IT, AND THEN FINALLY EAT IT.

BUT TODAY, FOOD IS A HIGHLY SPECIALIZED PART OF OUR CULTURE.

[OVERLAPPING CHATTER] MUTHUKRISHNA: LET'S SAY I WANTED TO MAKE SOME PRAWN AND VEGETABLE NOODLES.

THE FIRST THING I WANT TO DO IS TO FIND A RECIPE...

IDEALLY FROM SOMEONE WHO SPECIALIZES IN JAPANESE CUISINE.

FIRST, LET'S GO TO THE FISHMONGER AND GET SOME PRAWNS.

EBI, KUDASAI?

EBI.

[MAN SHOUTS IN JAPANESE] ARIGATO.

HAI, DOMO ARIGATO.

MUTHUKRISHNA: I NEED SOME MUSHROOMS, BUT WHICH ONES?

I DON'T KNOW, BUT SHE DOES.

WHICH MUSHROOMS DO YOU RECOMMEND FOR NOODLES?

THIS IS THE SHIITAKE MUSHROOM.

THIS IS A GOOD AROMA, A DEEP FLAVOR.

MMM, THAT'S LOVELY.

MUTHUKRISHNA: FINALLY, WE NEED SOME NOODLES.

ARIGATO GOZAIMASU.

MUTHUKRISHNA: EACH OF THESE SPECIALISTS RELIES ON A WHOLE NETWORK OF OTHER SPECIALISTS.

TAKE OUR FISHMONGER, FOR INSTANCE.

HE RELIES ON SOMEONE WHO KNOWS HOW TO CATCH THE FISH, HOW TO KEEP IT FRESH, HOW TO GET IT TO MARKET IN THAT FRESH STATE, HOW TO NAVIGATE THE LEGAL WATERS, HOW TO GET THE BEST PRICE, AND SO ON AND SO ON.

NARRATOR: ONLY NOW CAN MICHAEL GET ANOTHER SPECIALIST, A CHEF, TO COOK HIS MEAL FOR HIM.

MUTHUKRISHNA: NOW, THIS SORT OF SPECIALIZATION IS ABOUT EACH PERSON GETTING VERY GOOD AT SOMETHING VERY SPECIFIC SO THAT WHEN THEY POOL THEIR EXPERTISE, THEY BECOME A PART OF SOMETHING MUCH BIGGER AND BETTER THAN THEY COULD HAVE EVER ACHIEVED IF THEY HAD TO DO EVERYTHING ALL ON THEIR OWN.

AND THIS IS WHAT CITY LIFE AND CIVILIZATION IS ALL ABOUT-- HAVING ENOUGH PEOPLE SO THAT EACH OF US CAN FOCUS IN ON ONE VERY SPECIFIC THING AND GET VERY GOOD AT IT.

THE MORE PEOPLE WE HAVE, THE MORE NARROWLY AND DEEPLY WE CAN FOCUS, AND THE HIGHER WE CAN ALL CLIMB TOGETHER.

BUT SPECIALIZATION, BY DEFINITION, CREATES DIVISION: DIFFERENT JOBS, DIFFERENT PLACES TO LIVE, DIFFERENT SOCIAL CLASSES, DIFFERENT SOCIAL STATUS, DIFFERENT WEALTH.

LAND, FOOD, AND GOODS ARE NO LONGER OWNED BY THE COMMUNITY.

THEY BECOME THE PROPERTY OF A FEW AND OFTEN PASS DOWN THROUGH THE GENERATIONS WITHOUT BEING EARNED.

THIS IS INEQUALITY; SOME PEOPLE INEVITABLY BECOME RICHER AND MORE POWERFUL THAN OTHERS.

NARRATOR: ACROSS THE WORLD, THE ROAD TO CIVILIZATION ALWAYS LED TO INEQUALITY.

POLITICAL POWER, PROPERTY, AND WEALTH WERE NOW IN THE HANDS OF A RULING ELITE.

300 MILES FROM ASIKLI HOYUK ARE THE REMAINS OF THE ANCIENT TOWN OF ARSLANTEPE.

ARCHAEOLOGIST MARCELLA FRANGIPANE HAS SPENT 3 DECADES EXCAVATING THIS SITE.

SHE'S DISCOVERED THAT 5,500 YEARS AGO, AN ELITE ROSE TO POWER HERE.

BY ASSERTING THEIR STATUS OVER THE REST OF THE POPULATION, THEY BUILT UP GREAT PERSONAL WEALTH.

NARRATOR: THE COMMONERS COULD ONLY VISIT THE PUBLIC AREAS OF THE PALACE.

THEY ENTERED AND THEN TURNED A CORNER TO VISIT THE STOREROOMS.

[OVERLAPPING CHATTER] NARRATOR: HERE, THEY HANDED OVER WHAT THEY'D PRODUCED IN THE FIELDS... AND TOOK PAYMENT BY WAY OF FOOD IN RETURN.

[ALL SPEAKING NATIVE LANGUAGE] NARRATOR: JUST BEYOND THE STOREROOMS WAS A SMALL TEMPLE.

NARRATOR: INSTEAD, THEY WERE GREETED BY FORBIDDING WALL PAINTINGS, SOME OF WHICH HAVE SURVIVED FOR 5,000 YEARS.

NARRATOR: JUST BEYOND THE WATCHING EYES WAS THE CORE OF THE PALACE-- A COURTYARD WHERE PEOPLE PRESENTED THEMSELVES TO THE RULING ELITE.

AT ONE END OF THE COURTYARD, THERE WAS A RAISED PLATFORM.

THERE WAS A RAISED PLATFORM.

[OVERLAPPING CHATTER] [MAN SPEAKING NATIVE LANGUAGE] NARRATOR: BUT THERE'S A TWIST IN THIS TALE, A WARNING FOR ANY WOULD-BE DICTATOR.

THE WALLS ARE STAINED BY BURN MARKS.

[MEN SHOUTING] NARRATOR: ARCHAEOLOGISTS BELIEVE THIS IS EVIDENCE OF A REVOLT, THE COMMONERS TURNING AGAINST THEIR RULERS AND DESTROYING THEIR POWER BASE.

NARRATOR: WHAT WAS TRUE FOR ARSLANTEPE HAS BEEN TRUE EVER SINCE.

NARRATOR: INEQUALITY IS ONE OF THE GREAT PROBLEMS FACING ANY CIVILIZATION.

MUTHUKRISHNA: ELITES, AND EVEN INEQUALITY, ARE NOT NECESSARILY A BAD THING.

WEALTH GENERATORS AND SOCIAL ORGANIZERS ARE AN ESSENTIAL PART OF ANY SYSTEM.

RULES NEED TO BE ENFORCED, ARMIES NEED TO BE ORGANIZED, RESOURCES NEED TO BE EFFICIENTLY ALLOCATED.

THE TROUBLE IS WHEN THERE IS A MISMATCH BETWEEN THE LEVEL OF INEQUALITY AND YOUR CONTRIBUTION TO SOCIETY.

IF THE MISMATCH GROWS, THEN THE GLUE THAT BINDS CIVILIZATION TOGETHER STARTS TO COME APART.

HOW DO WE ENSURE THAT THERE'S A MATCH BETWEEN YOUR CONTRIBUTION TO SOCIETY AND THE LEVEL OF INEQUALITY?

HOW DO WE KEEP CORRUPTION IN CHECK?

HOW DO WE ENSURE THE WELL-BEING OF ALL PEOPLE?

THE FOCUS OF THESE QUESTIONS IS ALWAYS THE CITY.

THIS IS WHERE THE WEALTH IS.

THIS IS WHERE THE POWER IS.

THIS IS WHERE THE PEOPLE ARE.

THERE'S A COMPETITION GOING ON BETWEEN DIFFERENT SOCIETIES, DIFFERENT CITIES, AND DIFFERENT WAYS OF DOING THINGS.

THE WINNERS OF THAT COMPETITION ARE GOING TO BE THOSE THAT FIND A WAY TO HAVE PEOPLE GET ALONG AND TO FIND A WAY TO MAXIMIZE THE POTENTIAL OF MORE PEOPLE.

PERHAPS THIS IS THE SECRET TO TOKYO'S SUCCESS.

IT'S CLEARLY A RICH AND POWERFUL CITY, BUT IT FEELS LIKE WE'RE ALL ON THE SAME PAGE.

IT FEELS LIKE THERE'S A COMMON PURPOSE.

NARRATOR: CIVILIZATION WORKS BEST WHEN PEOPLE BELIEVE THEY'RE ALL IN IT TOGETHER.

NARRATOR: THE FIRST TIME A CITY GOT THIS FORMULA RIGHT WAS 4,000 YEARS AGO... NOT IN TURKEY, BUT 900 MILES FURTHER SOUTH, IN MODERN-DAY IRAQ.

[RADIO CHATTER] NARRATOR: ARCHAEOLOGIST JEFF ROSE IS PAYING A VISIT.

ROSE: TODAY, IRAQ IS ONE OF THE MOST HOSTILE ENVIRONMENTS IN THE WORLD.

I MEAN, JUST TO GET AROUND, I'VE GOT THIS CONVOY OF 4 VEHICLES WITH ARMOR PLATING, WHICH IS IRONIC BECAUSE THIS IS THE CRADLE OF CIVILIZATION.

THIS IS WHERE THE EARLIEST CIVILIZATION AROSE.

ROSE: ALL CIVILIZATIONS RISE AND FALL, BUT THIS ONE IN PARTICULAR, IN ITS HEYDAY, WAS MAGNIFICENT.

NARRATOR: THIS WAS ONCE A LUSH PLAIN BETWEEN TWO RIVERS, A LAND KNOWN AS MESOPOTAMIA, AND HERE WAS THE GREAT CITY OF UR.

4,000 YEARS AGO, IT WAS A SPRAWLING METROPOLIS OF 65,000 PEOPLE...

CENTERED ON A HUGE TEMPLE COMPLEX CALLED THE ZIGGURAT, RECONSTRUCTED IN THE 1980s BY SADDAM HUSSEIN.

ROSE: I CAN'T OVERSTATE THE IMPORTANCE OF THIS PLACE.

SO ELSEWHERE AT THIS TIME, PEOPLE WERE LIVING IN TOWNS, THEY WERE PAINTING WALLS, THEY WERE BUILDING PALACES FOR THE ELITES.

BUT DOWN HERE AT UR AND OTHER CITIES LIKE THIS, THEY WERE BUILDING THE BLUEPRINT FOR WHAT ALL CITIES TO COME AFTER WOULD LOOK LIKE.

THEY HAD CROSSED THE THRESHOLD INTO CIVILIZATION.

NARRATOR: WHAT WAS THE SECRET OF UR'S SUCCESS?

WHY DID CIVILIZATION WORK IN THIS CITY, WHEN OTHER LARGE SETTLEMENTS LIKE ARSLANTEPE HAD FAILED?

ROSE: I'M STANDING IN WHAT WAS ONE OF THE MOST FERTILE RIVER VALLEYS IN THE ENTIRE WORLD.

BUT TO MAKE THIS RIVER VALLEY WORK, YOU NEEDED TO ACTUALLY TRANSFORM THE LAND.

YOU NEEDED A WORKFORCE, AN ORGANIZED WORKFORCE OF ENOUGH PEOPLE TO DIG THE IRRIGATION CANALS TO BRING THE WATER INTO THE FIELDS, AND THEY HAD LOTS OF PEOPLE LIVING IN MESOPOTAMIA AT THE TIME.

THEY ALSO HAD THE RIGHT KIND OF FOOD; THEY HAD CEREAL GRAINS.

TO FUEL A CITY, YOU NEED CEREAL GRAINS.

[OVERLAPPING CHATTER] NARRATOR: MIX TOGETHER A CRITICAL MASS OF PEOPLE WITH ENOUGH FOOD TO FEED THEM AND A LOCATION WHERE THEY WANT TO LIVE, AND YOU GET A SELF-SUSTAINING CITY, A CIVILIZATION.

ARCHAEOLOGIST ELIZABETH STONE BELIEVES THERE'S ANOTHER REASON THIS CITY WORKED SO WELL.

SHE'S EXCAVATING THE RESIDENTIAL AREA OF UR, WHERE MOST OF THE POPULATION LIVED.

EARLY CIVILIZATIONS ALL HAVE KINGS, THEY ALL HAVE PRIESTS, THEY ALL HAVE PEOPLE AT THE TOP.

BUT WHERE THEY DIFFER IS WHAT HAPPENS TO THE LARGER POPULATION.

AND IN PLACES LIKE UR, I THINK THERE WAS QUITE A LOT OF EQUALITY AND QUITE A LOT OF SOCIAL MOBILITY.

WHEREVER WE DIG, EVERYBODY SEEMS TO BE DOING PRETTY WELL.

THERE'S A SENSE THAT, YOU KNOW, YOU'RE POOR WHEN YOU'RE YOUNG, YOU GET WEALTHIER AS YOU GET OLDER, AND YOU'VE GOT MORE KIDS WHO CAN WORK FOR YOU AND HELP YOU.

IT'S NO DIFFERENT FROM TODAY.

[OVERLAPPING CHATTER] STONE: THEY OWN THEIR OWN HOUSES, SO THEY INHERIT PROPERTY FROM THEIR FAMILIES.

THEY'RE ENGAGED IN BUSINESS.

THEY HAVE PRIVATE DOCUMENTS.

THEY WROTE ON CLAY, WHICH, IN THIS ENVIRONMENT, IS PRETTY MUCH INDESTRUCTIBLE, AND THEY WROTE ABOUT ALMOST EVERYTHING.

WE OFTEN GET CONTRACTS; THESE ARE GOING TO BE WHERE PEOPLE ARE SELLING A HOUSE, THEY'RE SELLING A FIELD OR AN ORCHARD OR THINGS LIKE THAT.

EVERYBODY WAS KIND OF MIDDLE-CLASS.

NARRATOR: DESPITE BEING RULED BY A KING, THE PUBLIC HAD A SAY IN THE RUNNING OF HIS CITY... AND SO UR AVOIDED THE DICTATORSHIP THAT BLIGHTED ARSLANTEPE.

[MAN COUGHS] STONE: I THINK IT'S VERY DIFFICULT TO HAVE REAL, LARGE-SCALE URBAN LIFE WITH HIGH LEVELS OF INEQUALITY BECAUSE PEOPLE ARE GOING TO BE LIVING CHEEK BY JOWL WITH SOMEBODY WHO HAS REALLY DIFFERENT TYPES OF ACCESS.

THE QUESTION IS, WHY SHOULD THEY STAY HERE?

IF YOU WEREN'T HAPPY, YOU COULD SAY, "WELL, TO HELL WITH IT.

I'M GOING TO GET OUT OF HERE."

SO IF YOU WANT YOUR CITY TO BE SUCCESSFUL, YOU NEED PEOPLE TO BE THERE, AND UNDER THOSE CIRCUMSTANCES, YOU HAVE TO GIVE THEM A PIECE OF THE PIE.

IF THEY FEEL THAT THEY'RE NOW PART OF SOMETHING LARGER, IF THEY HAVE A VOICE IN THE DECISION-MAKING, IF THEY HAVE ACCESS TO MORE GOODS BY BEING IN THE CITY, THEN IT'S WORTH THEIR WHILE TO LIVE IN THE CITY.

NARRATOR: BY CREATING A SOCIETY IN WHICH EVERYONE FELT INVESTED, THE RULERS OF UR BUILT A CITY THAT WORKED.

LITTLE WONDER THOUSANDS CAME TO LIVE HERE.

UR WAS A MELTING POT OF PEOPLE, IDEAS, AND INVENTION.

CREATIVITY SKYROCKETED.

TAKE THIS ARCHITECTURAL MARVEL, THIS THING CALLED A ZIGGURAT.

THIS WAS THE SYMBOLIC CENTER OF THE CITY.

THIS IS WHERE THE PRIESTESSES WOULD PERFORM THEIR RITUALS.

THIS IS WHERE THE PEOPLE WOULD CONGREGATE AROUND... [OVERLAPPING CHATTER] BUT THEY DIDN'T HAVE ANY STONE, THEY HAD NOTHING TO BUILD WITH, SO THE WHOLE THING IS MADE OUT OF MUD.

ROSE: THE ZIGGURAT'S JUST THE TIP OF THE ICEBERG.

IF YOU HAD CEREAL FOR BREAKFAST THIS MORNING, THAT'S BROUGHT TO YOU BY SOUTHERN MESOPOTAMIA.

THEY INVENTED LARGE-SCALE WHEAT PRODUCTION.

THE BOWL YOU HAD IT IN, WELL, THEY INVENTED THE POTTER'S WHEEL.

SO WHILE THERE ARE OTHER CIVILIZATIONS THAT EMERGE IN CHINA AND EGYPT AND INDIA AND MESOAMERICA, IT'S HERE IN SOUTHERN MESOPOTAMIA THAT'S THE ROOT OF WESTERN CIVILIZATION.

[OVERLAPPING CHATTER] ROSE: THESE PEOPLE WERE BURSTING WITH INGENUITY, BUT THEY DIDN'T HAVE MUCH TO WORK WITH IN THEIR ENVIRONMENT, SO THEY--FOR INSTANCE, THEY'D TAKE A BUNDLE OF REEDS, WHICH GROW JUST ALONG THE RIVERBANKS.

THEY COULD TURN THESE INTO BOATS, WHICH SAIL ALL THE WAY TO INDIA.

THEY WOULD ALSO...

THEY COULD JUST CUT THE BOTTOM OF THEM LIKE SO... AND YOU'D HAVE A STYLUS, WHICH IS ESSENTIALLY A KIND OF PEN.

FROM THIS, THEY INVENTED THE WORLD'S FIRST WRITING SYSTEM.

NARRATOR: EVERY WRITTEN WORD IN THE WESTERN WORLD CAN TRACE ITS ORIGIN BACK TO THE CUNEIFORM MARKINGS OF MESOPOTAMIA.

AND NOT JUST WRITING.

MATHEMATICS ALSO COMES DIRECTLY FROM MESOPOTAMIAN CIVILIZATION.

THEY USED REEDS FOR MEASURING DISTANCES.

SO THEY HAD TWO STANDARDIZED MEASUREMENTS.

IT WAS ALL BASED ON THE ANATOMY OF THE KING.

SO THEY WOULD TAKE THE LENGTH FROM HIS ELBOW CREASE TO THE TIP OF HIS FINGER, AND THAT WAS ONE STANDARDIZED MEASUREMENT.

AND THEN THE OTHER WAS THE FULL ARM SPAN, WHICH REALLY MEANS THAT THIS IS THE WORLD'S FIRST RULER, AND THIS LEADS TO THE BIRTH OF MATHEMATICS.

[OVERLAPPING CHATTER] ROSE: THE WAY THEY DID THAT WAS THEY USED THE DIVISIONS ON THEIR FINGERS-- 1, 2, 3; 4, 5, 6; 7, 8, 9 10, 11, 12-- AND THEN THEY HAD 5 FINGERS, SO MULTIPLY THAT, AND THEY GET A BASE-60 SYSTEM OF MATHEMATICS.

ROSE: NOW, THEY USED THIS SYSTEM TO TELL TIME.

HERE'S THE MIND-BOGGLING PART-- 60 SECONDS IN A MINUTE, 60 MINUTES IN AN HOUR.

THEY DIVIDED THEIR DAY UP INTO TWO 12-HOUR PERIODS.

SO WE STILL TELL TIME THE SAME WAY THE PEOPLE OF SOUTHERN MESOPOTAMIA DEVELOPED IT, AND THIS REALLY GOES TO SHOW HOW THE CITY IS THE ENGINE OF INVENTION.

NARRATOR: THE URBAN WAY OF LIFE PIONEERED AT UR WAS EXPORTED EASTWARD THROUGH ASIA AND WESTWARD THROUGH EUROPE.

THE CIVILIZATIONS OF GREECE, ROME, AND BYZANTIUM WERE ALL INHERITED FROM MESOPOTAMIA.

AND EVENTUALLY, THE SAME MODEL WAS TRANSPORTED ACROSS THE ATLANTIC TO THE NEW WORLD.

WE LIVE AS WE DO TODAY BECAUSE THEY DID IT FIRST.

THE CITY IS THE QUINTESSENTIAL EXPRESSION OF CIVILIZATION, A HOTHOUSE FOR IDEAS, AN ENGINE OF PROGRESS.

MUTHUKRISHNA: IF YOU LOOK AT THE TALLY SHEET OF HISTORY, IN THE FIRST 200,000 YEARS BEFORE THE FIRST CITIES, WE INVENTED STONE TOOLS, BOWS AND ARROWS, CANOES, SEWING, AND POTTERY.

NOW, THAT'S QUITE IMPRESSIVE, AND CERTAINLY MUCH MORE THAN OUR CHIMP COUSINS HAVE MANAGED TO PULL OFF.

BUT IN THE FIRST 2,000 YEARS SINCE THE ADVENT OF CITIES CAME THE ALPHABET, MATHEMATICS, WRITING, CEMENT, RESERVOIRS, SEWERS, AQUEDUCTS, SOAP, CANDLES, CURRENCY, SILK, PAVING, CANALS, FURNACES, AND SO ON AND SO ON.

MUTHUKRISHNA: THE MORE VIEWPOINTS, AND THE MORE DIVERSE THE VIEWPOINTS THAT YOU HAVE ACCESS TO, THE BETTER OFF YOU ARE.

THAT'S THE APPEAL OF THE CITY.

CITIES ACT ALMOST LIKE COLLECTIVE BRAINS, WHERE YOU HAVE ACCESS TO THE VIEWPOINTS AND TALENTS OF MILLIONS OF PEOPLE-- THIS FIZZING, BUZZING CONNECTIVITY OF MINDS TRYING TO LEARN AND SHARE WITH EACH OTHER.

THE MORE MINDS, THE MORE CONNECTIONS, THE MORE INNOVATION.

MUTHUKRISHNA: SCIENCE FICTION WRITERS SOMETIMES LIKE TO IMAGINE SOME KIND OF ALIEN SPECIES CONNECTED BY A SINGLE HIVE MIND.

BUT IN SOME SENSE, THAT'S WHAT HUMANITY IS LIKE TODAY, LIVING TOGETHER IN THESE MEGA-CITIES.

THE HUMAN BRAIN CONTAINS BILLIONS OF NEURONS, BUT ITS POWER COMES NOT SIMPLY FROM THE NUMBER OF NEURONS, BUT BY THE INTERCONNECTEDNESS IN THESE ELABORATE NETWORKS SPANNING TRILLIONS OF CONNECTIONS.

IN JUST THE SAME WAY, OUR CITIES CONTAIN BILLIONS OF HUMAN BEINGS, BUT THEIR POWER COMES NOT SIMPLY FROM THE NUMBER OF PEOPLE, BUT THE INTERCONNECTEDNESS OF PEOPLE, AND THESE ELABORATE SOCIAL NETWORKS SPANNING TRILLIONS OF CONNECTIONS AND CONVERSATIONS.

IN MANY WAYS, THE CITY AND CIVILIZATION ITSELF IS A PROJECTION OF OUR OWN BRAINS.

THE CITY IS MUCH MORE THAN THE SUM OF ITS CITIZENS.

I THINK IT CAN BE A LITTLE THREATENING TO THINK OF YOURSELF AS A SINGLE NEURON IN THIS GIANT, CONNECTED, COLLECTIVE BRAIN THAT WE CALL HUMANITY.

BUT I THINK THAT'S BOTH FASCINATING AND HUMBLING.

NARRATOR: IT'S ESTIMATED THAT EVERY WEEK FOR THE NEXT 3 DECADES, ANOTHER MILLION AND A HALF PEOPLE AROUND THE WORLD WILL MOVE TO THE CITY.

JUST LIKE OUR ANCESTORS, WE'RE SEDUCED BY THE LURE OF BEING TOGETHER AND SHARING IDEAS.

THE CITY--A CORNERSTONE OF CIVILIZATION.

VO: Next time on First Civilizations... For any civilization to succeed, it must meet the needs of its people.

This requires a system of exchange.

Man 1: Tradal exchange was the economic and social glue that stitches people together.

Woman 1: Trade enables the society to progress.

Man 2: That's what has eventually enabled us to build a civilization that is so complex.

VO: But how did trade shape the course of civilization?

Next time on First Civilizations.

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