Original subtitles

In the year 1586, towards the end of the 16th century,

a Portuguese missionary called Antonio de Magdelena

was part of a group exploring the deeply forested interior of Cambodia.

They traveled through the soupy heat of the Cambodian jungle,

surrounded by the fluttering of banana palms and the chattering of cicadas.

Their Cambodian guides had told them that the ruins of an enormous city

lay somewhere here in the jungle, but they didn't know the scale

and grandeur of what awaited them. Magdelena was killed soon after in a

shipwreck but before he died, he managed to relate

to a friend who wrote down all that he saw of these

sprawling ruins in the jungle.

The city is square, with four principal gates,

and a fifth which serves the royal palace.

The gates of each entrance are magnificently sculpted,

so perfect that they look as if they were made from one stone.

In the middle of the city is an extraordinary temple.

The missionaries were astonished. This city

was grander and more magnificent than anything they had ever seen

back home in Europe. Great banyan trees and creeper vines

clambered over the ruins. The city seemed completely abandoned but here and

there, Buddhist monks in tangerine robes still

performed rituals among its crumbling shrines.

Half a league from this city is a temple. It is of such extraordinary construction

that it is not possible to describe it with a pen.

It is like no other building in the world;

it has towers and decorations and all the refinements

which human genius can conceive of.

Amazed at the site, the Portuguese asked their guides a flurry of questions.

Who had built this place? How had they constructed such vast

works of architectural genius, and why, after everything they'd built, had they

left it all behind? But the guides didn't know. They said

only what their parents had passed down to them; that these great stone edifices

had been built here over a period of centuries

by more than 20 kings. The Portuguese asked what the name of

this great metropolis had been, but the guides didn't know that, either.

They used just one word to describe it, which in the old language of Cambodia

simply means "the city" and it has come to be the name

by which these ruins are known. This word was "Angkor".

My name is Paul Cooper and you're listening to The Fall of Civilizations

Podcast. Each episode, I look at a civilization of

the past that rose to glory and then collapsed into the ashes of

history. I want to ask what did they have in

common? What led to their fall and what did it

feel like to be a person alive at the time who witnessed the end

of their world? In this episode, I want to tell the story

of the civilization that has given us some of the world's

most iconic ruined places; that's the Khmer Empire of medieval

Cambodia. I want to explore how this great

civilization rose to a size and wealth virtually unprecedented in the world at

this time, how it overcame the formidable

challenges of its climate and landscape, and all the factors that led to its

final and dramatic collapse.

Stories of European explorers cutting their way through the jungle and

stumbling on the ruins of lost cities have always been popular in the western

imagination, but it's worth noting that although

abandoned and left for the jungle to reclaim,

Angkor has never really been lost. Since its population left in the mid

15th century, it has been a site of constant religious

worship. Its name was forgotten, its streets were

taken over by monkeys, and banyan trees clambered over its

crumbling stones. But still, farmers worked the fields

nearby, and Buddhist monks have always visited

this ancient city to worship among its quiet ruins.

The Khmer Empire ruled much of Southeast Asia from the 9th to the 15th century.

At its height, it covered an area that today includes much of Thailand and

Cambodia, as well as Vietnam and Laos.

At the empire's heart was the mega- -city

of Angkor.

Angkor covers an area of over one thousand square kilometers,

larger than New York City today, and between the 11th and 13th centuries,

its wider agricultural area is thought to have supported at least 1 million

people, or 0.1 percent of the world's population.

That means that for a period of a few centuries, one in every thousand person

in the world lived in the city of Angkor. So, what

happened to turn this once glorious city of gold

into a crumbling ruin? How could the Khmer Empire collapse so

completely, and what could this teach us about the

challenges we face in our own modern world?

After the first European travelers witnessed the ruins of Angkor,

a steady trickle of visitors began to descend on the magnificent ancient city.

Before long, everyone had their own theories about who had built it,

as this early European source shows.

We suppose that the founders of the kingdom

of Siam came from the great city which is situated

in the middle of a desert in the kingdom of Cambodia.

There are the ruins of an ancient city there which some say

was built by Alexander the Great or the Romans.

It is amazing that no one lives there now;

it is inhabited by ferocious animals and the local people say it was built by

foreigners.

One account written in Madrid in 1647 even argued that this city must have

been built by the Roman Emperor Trajan, without explaining quite how he might

have got there. In fact, virtually nobody in Europe gave

credit to those people who had actually built these great temples and palaces;

that's the people of Cambodia who called themselves

the Khmer. The Khmer are one of the oldest ethnic groups of

southeast Asia. They arrived in the region from probably

the area of Southern China over 4,000 years ago. They were one of

the first people in the world to use bronze

and to invent the number zero, and they developed the earliest alphabet

still in use in Southeast Asia. The Khmer were a proud people but for

much of their early history, they were ruled over by others.

A great Empire called Chenla had once ruled the lands of Cambodia

and since its collapse in the 8th century,

the region had been broken up into a set of small Khmer kingdoms

ruled by local lords. But one man would soon be born who would

forge these disparate kingdoms into an empire that would once again

rule over the entire region and become one of the world's great

powers. The beginning of this empire is

conventionally dated to the year 802 and it would be founded thanks to a man

who would call himself Jayavarman II.

Little is known about the early life of this shadowy warrior.

Jayavarman II seems to have written no inscriptions

or left many clues about where he came from.

He appears to have been of aristocratic birth,

and began his career in the southeast of present-day Cambodia.

But the name he chose for himself tells you everything you need to know;

Jayavarman was the name of the last King of the Empire of Chenla,

and in choosing the name Jayavarman II, this Khmer revolutionary

was making a very clear statement. 'I am the second coming of the kings of old,

and I will return Cambodia to its glory days.'

At this time, the fractured mess of Khmer kingdoms across Cambodia

were all under the umbrella rule of a power known in the inscriptions

as Java. Some historians have argued that this is the island of Java

that today is part of Indonesia, but others believe

that it refers to the Cham people of nearby Southern Vietnam,

who the Khmer sometimes called chvea. I think this is the most likely scenario,

since the rivalry between the Khmer and Cham peoples will

blaze on for centuries, and we'll hear a lot more about it over

the course of this episode. The Cham people got their name from the

Sanskrit word campaka, a type of tree known as the

yellow jade orchid, but the Cham people were not as delicate

as their name might suggest. From their capital in Vijaya, now near

the modern Vietnamese city of Qui Nyon, the Cham

ran a powerful trading empire that built striking

red stone towers and could muster vast fleets of ships with dragon-headed prows

that crushed any resistance to their rule.

But their dominion over the Khmer people was soon to be challenged.

At heart, Jayavarman II was a revolutionary.

He wanted to forge an independent, united kingdom for the Khmer people,

and his campaign of rebellion was immensely successful.

He first seized the city of Vyadhapura in the southeast,

and then pushed up the Mekong River to take Sambhupura.

He and his followers swept from southeast Cambodia to the northwest

and everywhere he went, people joined his army.

One rare inscription shows how Jayavarman's campaign

seemed to happen almost miraculously. For the prosperity of the people in this

perfectly pure, royal race, great lotus which no longer

has a stalk, he rose like a new flower.

But the more power Jayavarman amassed, the more resistance he faced,

and in the west, he found that many Khmer leaders were still

loyal to the King of Champa. They fought back against Jayavarman

and managed to force him into a retreat. Bloodied and humiliated, he and his

followers retreated to the mountain range in Cambodia

known as the Kulen, or 'Lychee' Hills. Despite its beautiful name, this was a

tough terrain; a range of stony hills overgrown with

jungle, where creepers and roots clambered over

the rocks. For a time, it must have seemed like all

was lost, but as he gathered the remains of his

forces together, Jayavarman knew that it would take more

than just military might to unite the Khmer peoples.

He decided that what the people of Cambodia needed was not a warlord,

but a king. He would crown himself something that had never before existed,

the King of the Khmer, and to do this he would have to devise

an elaborate and mystical ceremony. The most valuable inscription concerning

Jayavarman II is the one dated to the year 1052,

two centuries after his death. It's found at the temple

of Sdok Kak Thom in present-day Thailand. His Majesty Jayavarman came from Java

to reign in the royal city of Indrapura. A brahman proficient in the lore of

magic power, came from Janapada in response to His

Majesty's invitation to perform a sublime rite which would

release the kingdom from the tyranny of Java.

This Hindu ceremony was known as the deva raja,

or the god-king ritual. What exactly was involved in the ritual

isn't recorded but from similar ceremonies in India,

we can imagine perhaps an animal sacrifice

along with the burning of sacred kusha grass and incense,

and the chanting of incantations in the ancient language of Sanskrit.

But whatever it involved, we know the effect this ceremony had.

By the time the ritual was finished, Jayavarman had established himself

not just as a King of the Khmer but as a kind of deity,

and the symbolic power of this ritual seemed to work.

When the remaining kingdoms of the Khmer heard that a god-king had been crowned,

their will to fight dissolved. Jayavarman was cunning; through a smart

program of military campaigns, alliances, marriages, and land grants,

he gradually gathered all the remaining kingdoms of the Khmer

under his banner. He had achieved the unthinkable,

a unification of Cambodia that stretched from China to the North

and bordered the old enemy of Champa to the east, the ocean to the south,

and to the west, a place identified by one inscription

as "the land of cardamoms and mangoes" which is likely

Myanmar or Eastern India.

Once his conquest was complete, Jayavarman built a capital

at a place he called Hariharalaya, and it would be a city suited for a

god-king. He built his palace on high ground and

nearby dug a vast reservoir, marshalling

enormous workforces to build embankments, drain swamps, and dig ditches. He even

diverted the course of the Siem Reap River to build his new

capital. The ambition and scale of this project

was vast and completely unprecedented in the

region. Everything that was built for the

new god-king was designed to testify to that direct link

that existed between him and the gods. In Hindu belief, the gods Shiva, Vishnu,

and the rest of the pantheon, live on a great mountain called

Meru, similar to the idea of Mount Olympus

in ancient Greek mythology. Mount Meru is believed to be surrounded by a sea of

milk, and when Jayavarman built his capital at

Hariharalaya, he designed it to emulate this cosmic

image: his palace on a hill overlooking the

great reservoir. This building work must have been truly

awe-inspiring for the people of the time. It set the

tone for the ambition and scale that would mark the

constructions of the Khmer, but it would be Jayavarman's successors

that would transform his kingdom into a truly great empire, and the vast

grandeur of their constructions would reach heights that even Jaya-

-varman could never have imagined.

Before we go on, I'd like to paint a picture of the landscape

over which this great drama will unfold. 50 million years ago, the Indian tectonic

plate collided with the Eurasian plate, forcing

up the Himalayan mountain range into the highest peaks in the world, and

creating the wide Tibetan Plateau. This

mountainous area, about five times the size of France, is

sometimes called the Third Pole since its tens of thousands of

glaciers and lakes serve as a kind of water tower for the

whole region. From this great plateau, several of the

world's longest rivers find their beginnings,

including the Yangtze, the Indus, and the Mekong.

The Mekong is the world's 12th longest river.

From the Tibetan Plateau, it wends for 4,300 kilometers through China's Yunnan

province and down through Laos, Cambodia, and

Thailand, finally branching out into a delta at

the south coast of Vietnam. This river is utterly teeming with

life; its ecosystem has the second-highest

rate of biodiversity in the world after only the Amazon River, containing

freshwater dolphins, giant stingray, softshell turtles,

and giant catfish. The Mekong River flows right through the center of

Cambodia and much of our story will take place on the shores of a vast

freshwater lake called Tonle Sap, right in the middle of

Cambodia. For most of the year, the lake drains its

water into the Mekong River, but when the southwest monsoon season

begins in June, the Mekong suddenly swells into a raging

torrent, and the river that normally drains the

lake suddenly reverses its flow, filling this body of water until it has

a maximum length of 250 kilometers, with the width of a hundred kilometers.

In these months, the lake looks like an inland sea,

stretching off into the horizon as far as the eye can see.

Today, the villages around the lake are famous

for their houses perched on top of towering stilts,

raising them 10 meters into the air, or over three stories.

That's because during the monsoon, the lake's water level

rises from one meter deep to ten times that amount.

One Chinese visitor to ancient Angkor described this remarkable fluctuation,

although he slightly exaggerates the height of the waters.

The high water around the freshwater seas can reach some

24 meters, completely submerging even the very tall trees except for the

tips. Families living by the shore all move

to the far side of the hills, but the challenges that the great lake

presented to ancient people were offset by some incredible benefits.

Tonle Sap has the highest concentration of freshwater fish in the world,

thanks to the mineral-rich sediment carried into the lake by the annual

floods. As well as fish from the lake, the Khmer

people of this region cultivated rice.

The rice we know was first domesticated in the Yangtze River basin in China

around 10,000 years ago, bred from marsh grasses

that grew in flooded and swampy ground. Due to this, rice fields have to be

constantly inundated with water for the crops to grow. Because of this

need, the Khmer soon became experts in the

control of water in the landscape, and this

expertise would mean that the empire only just

beginning on the shores of this lake would boom to immense size and grandeur.

Every king who followed after Jayavarman II

would follow his example in conducting the Hindu ritual of the deva raja

to crown themselves as the god king of Cambodia.

This title was not just a metaphor; for much of Angkor's history, its king

was both the wielder of executive power and the center of an opulent religious

cult emanating from the great temples of its

capital. The Hindu religion, originating in India,

had a long history in Southeast Asia, and Cambodia at this time was what's

known as an Indianized kingdom. An ancient Khmer folktale tells the

story of how the lands of Cambodia were

founded. A long time ago, in the time of myths and

legends, there was a Prince of India named

Kaundinya, who was descended from the god of the sun.

One day, Kaundinya heard a mysterious voice calling out to him,

telling him to set out on a journey to the land of gold where he would become

king. This was a dangerous journey by sea,

following the monsoon winds and dangerous ocean currents,

but he gathered his courage and set out. Upon nearing the foreign coast of the

land of gold, Kaundinya's ship was attacked by a

fierce sea creature. It was a serpent woman with sharp fangs

and a whipping tail. Her name was Nagisoma and she was the

beautiful daughter of the serpent king. Kaundinya fought her, and after a long

battle, he emerged victorious. He spared the serpent woman's life and

she was impressed with his skill; she offered her hand in marriage. In

celebration, Kaundinya hurled his golden lance at

the coast, and where it landed he resolved to build his royal city in

the land of gold, which he gave the name "Kambuja".

This Khmer story, like many legends of its kind,

may have some grain of truth to it. The Kambuja that was founded with the

throwing of that golden lance is of course the original name for

Cambodia, and the story expresses how the Khmer

culture traced their lineage back to India.

At this time, the cultural impact of India in this region was immense.

Great Indian superpowers like the Pallava and Chola Empires

had already risen and fallen, spreading their culture

across the whole area of Southeast Asia. Just as people all around the world

today drink American sodas and fast food, so in ancient

Asia, nations were slowly adopting the culture,

religion, and customs of India. The kingdoms of Southeast Asia adopted

India's hierarchical social structure based on caste,

its Hindu myths and philosophies, and perhaps most importantly,

the language of Sanskrit.

Sanskrit is a language that originated in north India.

It was once a living language but today it occupies a similar role to Latin in

the European tradition. It's no longer spoken by ordinary people,

but has become a language of scholarship and religion.

In the western world, it is most commonly encountered in our yoga classes.

You may think that this ancient Indian language is about as foreign to you as

you could imagine, but that's not actually true. In fact,

Sanskrit is part of the Indo-European family of languages,

the same family as our own English. This means that there are actually some

Sanskrit words that you might recognize. For instance, the Sanskrit word for 'tooth'

is 'danta'. This shares a common ancestor with

our English word 'dentist' which is passed through French,

Medieval, then ancient Latin, ancient Greek,

and finally the theoretical language we call Proto-Indo European which branched

off around 5,000 years ago.

At the time of the Khmer Empire's flourishing, classical Sanskrit

became the language used among the elite of Southeast Asia,

just like Greek and Latin were once required learning among Europe's

nobility. But it's important to note that while

the elites, the wealthy, and the nobles of Angkor

were enraptured with Sanskrit and Hinduism, a great many of the common

people of Cambodia were not Hindu;

they were either Buddhist or they followed their own ancient

folk rituals that asked favors of the spirits who lived in the trees and the

mountains. This division between the wealthy Hindu

nobles and the different beliefs of the common

people would form a stress line across Cambodian society.

We will return to this fracture a number of times over this episode,

as it causes ruptures and conflicts and ultimately threatens to tear

the entire empire apart.

The Khmer king who had built the first great city

at the site of Angkor was a man named Yashovarman.

He was the son of a King named Indravarman.

Perhaps you've already noticed something of a pattern with the names of

these Cambodian kings. In fact, every king of the Khmer for the

next 500 years would follow this convention, adopting a

name that ended in 'varman', a Sanskrit word that means 'shield' or

'armor'. The name Jayavarman, for instance, means

something like 'victory shield'. When the old king

Indravarman died, he left behind two sons.

One of these brothers was Yashovarman. His name means something like 'glory

shield', and he was a vain and short-tempered

prince. He was the eldest son and he must have

expected that one day he would sit on the throne

that his father now occupied, but it seems that for whatever reason,

Yahshovarman was not his father's favorite.

Instead, the old king named his younger brother

the heir to the throne. Insulted and humiliated,

Yashovarman flew into a rage. He immediately began to gather his

armies and a bitter civil war erupted across the country. The fighting

was vicious, with armies clashing on the land and

fleets of boats battling on the great lake

Tonle Sap, that beating heart of the Khmer world.

Inscriptions of the time claimed that Yashovarman was a fierce and

competent commander and he may well have been, but it's worth

mentioning at this point that the kings of the Khmer had a great

weakness for flattering themselves in their own inscriptions, and those

written by Yashovarman are some of the worst offenders.

A lion-man, he tore the enemy with the claws of his grandeur.

His teeth were his policies, his eyes were the holy scriptures.

For obvious reasons, it's difficult to rely solely on the way these kings

describe themselves in their own inscriptions,

but I think each one does tell us something interesting.

That is, how these kings wished themselves to be seen.

Lion-man or not, we do know that after much bitter fighting,

Yashovarman finally defeated his younger brother

and claimed the crown for himself.

But Yashovarman was still clearly hurt by his father's decision.

When he was finally crowned king, he refused to claim the throne through his

father's line. Instead, he had his royal scribes concoct

an elaborate new family tree that completely bypassed his

father, just as his father had tried to bypass

him. Yashovarman's mother was now the true

royal one, descended from the ancient kings of that

fallen empire of Chenla. Despite this tendency for spite,

Yashovarman seems to have been an effective ruler, although from the

inscriptions he continued to commission, it's clear he never quite lost that

original weakness for flattery. In all the sciences and all the sports,

in the arts, the languages, and the writings, in

dancing, singing, and all the rest, he was as clever as if he had been the

first inventor of them. One area that we can be sure

Yashovarman excelled in is construction. In just the first year

of his reign, he built over a hundred monasteries across the kingdom.

He ruled for another 20 years from 889 to his death in the year 910,

and during this time, he decided to build a new capital.

Susceptible as ever to flattery, he named this city after himself,

calling it Yashodhapura, but today we know it by the name

Angkor. We may never know why Yashovarman had such a mania for

construction, but one legend suggests a possible

explanation for why this king wanted so desperately

to leave his mark on the world. In some traditions, Yashovarman went by

another name; the Leper King. Leprosy

is caused by a bacterial infection that can remain dormant in the body for up to

20 years before showing its symptoms. It was one of the most feared diseases

right across the ancient world, since it rendered horrible deformities

and skin lesions to its sufferers. It's not unknown in history for a

king to contract leprosy; a 12th century King of Jerusalem known

as Baldwin IV ruled for 10 years while suffering from

the disease. Modern bone analysis has shown that

the Scottish King Robert the Bruce also suffered from it. Today, a melancholy

monument in the northwest corner of one Royal Square in Angkor has become

a kind of shrine to Yashovarman. That's because of a statue there that

depicts the Hindu god Yama, the god of death and lord of the

underworld. This statue is eaten away by moss and

discolored by rain, and its patchy stone has given rise

to a legend that it depicts the harrowed flesh of

the Leper King Yashovarman.

We can never know how much truth there is to this legend,

but if you'll allow me just a moment of imagination,

I do wonder whether this explains the absolute drive of this

king to build these vast and stunningly beautiful palaces beside the great lake,

but as his flesh decayed around him and he felt the certainty of his death draw

closer, he felt an ever greater need to make his

mark on the world, a mark that would last long after his

body had finally given in to his disease, and that would leave his name forever

stamped on these crumbling stones. But again, we can never say for sure.

From the foundations laid by the Leper King Yashovarman,

Angkor's Empire grew and flourished until it was the most powerful in Southeast

Asia. There were a number of factors behind

this great success story; the first of these was the ruler's

status as god king. This cemented his royal authority and it

allowed the peasants of Angkor to see service to their king

as a kind of religious devotion. The second was the empire's efficient

and decentralized tax system. This also relied on the close ties

between the god king and his religious establishment.

Each village in the Khmer Empire had its own temple,

and this temple wasn't just a religious building;

it was also an administrative center. Each temple was run by a powerful family

in the area who were responsible for collecting

taxes from the people who lived there. They would use these taxes to support

the functioning of their own lands, paying their labourers and soldiers, and

supporting their own luxurious lifestyles, but anything left

over would then be funneled back to the royal

treasury in Angkor.

The status of these families depended on how much money they could send to the

king, and so they competed bitterly to swell

the royal funds. This simple but effective system led to

a swift expansion of the empire's economic capacity.

The elites who ran the village temples worked as fast as they could to expand

their taxable lands and cut down as many trees as they could

to make way for new farmlands, which soon covered the vast area of

Cambodia's highly-fertile central lowlands. The final factor in the

Khmer's success was their ingenuity in the management of

water.

In its early history, the enormous lake and the floodplains around

Angkor allowed its people to conduct multiple rice harvests throughout the

year, but as Angkor grew into a true city,

strain on this agricultural system increased.

To deal with the increased demand of the population,

Angkor's people developed an ingenious system of water control

that turned their capital into what is known as a hydraulic city.

If you are able to soar like a bird over ancient Angkor,

you would see the whole land below you etched out in remarkably regular lines

like the marks on a circuit board. These lines would flash in the sun as

you passed over them. They are canals and inlets that allow

water to flow around the whole city, inundating its

fields in a vast interconnected circulatory

system. They built complex junctions into their

waterways using canals with multiple bends in them

when they wanted a slow, steady flow of water, and long, straight

canals when they wanted a fast and direct flow into the reservoirs.

As water drains from the Kulen hills in the north,

the engineers of Angkor channelled it into two enormous reservoirs

known as barays. These were the largest human constructions built

until the modern industrial era. The so-called west baray measures

roughly 8 x 2 kilometers, or the size of 2,000 football

pitches, while the east baray is only a little

smaller. The ancient engineers didn't dig the

earth out; they built up instead, heaping up

enormous mounds of earth into banks and then diverting rivers and canals to

fill them. These enormous banks could be as much as

a hundred meters wide and ten meters tall, containing

eight million cubic meters of earth.

Today, the west baray is still an enormous lake,

but the east baray contains no water. Farmers grow their crops on what was

once its lake bed, but its outlines remain clearly visible

in the landscape. Together, these barays make Angkor one

of the human constructions most readily visible from outer space.

These fast reservoirs served a dual purpose;

they acted as overflow tanks in the monsoon season,

preventing the rice fields from flooding in an uncontrolled way,

but they also allowed the Khmer to store water through the dry season

when the rain didn't fall. Through the dry months,

the Khmer could drain as much water from the reservoirs as they needed,

diverting it through their complicated system of channels

into their fields, possibly using wooden lock gates

to give greater control over the direction of the water.

Angkor's water machinery is so vast and complex

that many of its components are still a mystery to us,

but thanks to this system, rice could now be harvested

all year round. One Chinese visitor to the ancient Khmer Empire,

writing in the 14th century, described the effectiveness of this system.

For six months, the land has no rain at all.

In general, crops can be harvested three or four

times a year. This huge agricultural potential

allowed the city of Angkor to boom to unprecedented size.

While London had a population of less than 20,000 people

in the 12th century, central Angkor may have contained as many as a quarter

of a million.

Like a modern city, it was divided into a grid

of regular city blocks. A traveler or pilgrim arriving at Angkor during the

rainy season might have sheltered beneath the canopy

of a roadside rest stop and warmed their hands by the fire, heard

the chanting of monks in the temples nearby,

the sound of bells, and the smells of incense and animals.

They might have crossed a bridge wide and strong enough to hold the king's

elephants, and seen the green water of the

reservoirs rushing beneath them. Today, our cities are made up of dense

residential, commercial, and administrative buildings.

We've banished our farmland to the countryside outside the city limits

but in Angkor, every available plot of land

would have been given over to farmland which shared space with temples and

palaces. The whole city would have had the feel

of an enormous village, or thousands of villages bleeding into

one another.

So, these are the three main strengths, the three pillars that allowed the Khmer

Empire to boom to such enormous size. Firstly, they had a powerful central

authority in the king, who was also worshipped as a god.

Secondly, they had an effective tax system that

incentivized growth and competition among regions.

Finally, they were experts at managing water in a

way that got the maximum amount of food out of the landscape.

These three pillars supported a system that would allow the Khmer

to build and flourish for over 400 years, but for a number of reasons, this period

of flourishing wouldn't last.

That's because for each of Angkor's strengths, it had a weakness.

Each of these three pillars contained a fatal crack.

Firstly, while its king was powerful, his power depended on his status

as a god-king. This meant that the Hindu belief of Angkor's people

had to be maintained and any shift in religion

could undermine the entire system of royal power.

Secondly, while Angkor's tax system incentivized growth,

it also encouraged over-exploitation of the land,

resentment among the exhausted and over-taxed peasants,

and environmental damage in the form of deforestation.

Finally, the Khmer's greatest strength, their incredible skill at water

management, also had the potential to become their

greatest weakness.

The vast water network that laced the city of Angkor and the whole of Cambodia

at this time would have required a huge amount of

resources and labor-intensive maintenance.

It needed constant effort to repair damaged banks and inlets,

and to clear the canals of the silt that was always building up at their bottoms,

washed down from the hills. Angkor's water system

was so complex and interdependent that under a sufficient stress,

a single failure could cause a cascade effect,

rippling throughout the whole network and bringing the world's largest city to

its knees. All of these factors would come into

play as the Khmer Empire reached its height,

and these three pillars came under increasing stress.

As so often happens throughout history, the rise of one empire begins with the

fall of another. To the north of the Khmer kingdom,

China's Tang dynasty had presided over a golden age that

lasted nearly 300 years. It was a flourishing time of arts and

culture, when prosperity was widespread and trade

boomed, but around the time of King Yashovarman, the

Tang dynasty was entering into a nosedive.

Huge armies of bandits now ravaged China's countryside

and sacked its cities, smuggling salt, and ambushing merchants. Finally,

emperors were assassinated and palace coups led to the disintegration

of the entire Tang dynasty.

Now five different dynasties fought over who would rule

China and meanwhile, Southern China fractured

into ten warring states. This period of chaos in China would

provide an opportunity for an ambitious young empire like the

Khmer. Kings like Indravarman and Yashovarman

now had a free hand to expand their territory inland,

and the anarchy in China meant that merchants and traders

would look to the golden towers of Angkor to provide security on the roads.

By the 12th century, the Khmer had come to totally dominate the lands of

Southeast Asia, and the magnificence of their

architectural works were a testament to the glory that their

empire had achieved.

The most famous of all Khmer monuments today is Angkor Wat.

By some estimations, it is the largest religious structure

ever built, four times larger than the Vatican City in Rome.

Angkor Wat was built out of perhaps as many as

10 million sandstone blocks, each weighing up to 1.5

tons. The stone was quarried from the sacred Kulen hills 40

kilometers to the north, cut out of the bedrock by teams of

workers using iron tools, and the blocks were then floated down to

the lowlands on barges that traversed the wide canals.

The amount of building material used to construct Angkor Wat

is greater than the great pyramid of Khufu at Giza,

and if the entire city of Angkor is taken into account,

more stone was used in its construction than in all the pyramids of Egypt put

together. Ankor's blocks of sandstone are held

together without mortar, shaped so perfectly that the gaps

between the stones are often invisible.

Like most of the Khmer's Hindu temples, Angkor Wat is designed to represent

Mount Meru, home of the gods. Its five kilometer moat

encloses three rectangular galleries, each

raised above the next, and its five towers

are designed to look like lotus buds about to bloom.

When the French explorer Henri Mouhot was shown the ruins of Angkor Wat in the

19th century, now overgrown and clutched in the

embrace of huge banyan and silk cotton trees,

he wrote back to the French colonial authorities about what he saw.

One of these temples, a rival to that of Solomon and erected by some ancient

Michelangelo, might take an honorable place

beside our most beautiful buildings. It is grander than anything left to us

by Greece or Rome. The ingenuity of the people

who built this temple can't be overstated. The medieval Khmer

built Angkor Wat in just under 37 years, while at the same time, the Normans took

centuries to build their own cathedrals.

Angkor Wat was built by the Khmer King Suryavarman II

in the early 12th century. He had a passion for architecture that would turn

his capital into one of the world's wonders,

but rather unfortunately, both for himself and the kingdom,

Suryavarman also had an insatiable appetite for warfare,

and unlike some of his predecessors, he showed

absolutely no skill in it whatsoever. A low-relief carving in the south

gallery of Angkor Wat shows King Suryavarman as he would like

to be seen, as a mighty warrior riding into battle

on the back of an elephant. He looks the perfect image of a Khmer

warrior; his chest covered with armor, a sharp

weapon in his right hand, and hordes of foot soldiers below armed

with spears and shields. But the reality was quite different.

It's true that Suryavarman liked to lead his men into battle,

and he did so on many occasions. Throughout his reign, he had set his

sights on the two coastal nations that made up the area

of what is today Vietnam. One of these we've looked at already,

the land of Champa who had once ruled over the disparate Khmer kingdoms of

Cambodia before being expelled by Jayavarman II.

While the Khmer were an inland people, the Cham

were seagoers, mariners, and traders. One low-relief carving at the Ankorian

temple called the Bayon shows Cham's sailors fighting against

the Khmer, sailing in long rowing boats with

dragon-headed prows, and umbrellas overhead to shade them

from the sun. To the north of Champa was a kingdom

called Dai Viet, home of the Viet people who give their

name to the modern country of Vietnam. Vietnam in those times was divided

between these two kingdoms, Champa and Dai Viet, and interestingly,

the border between them was close to the same line that split the country during

the Vietnam war, famously separating north and south

along the 17th parallel. King Suryavarman was determined to

conquer these ancient coastal kingdoms and take advantage of the rich traffic

of trade that passed down their coastlines from China.

He embarked on three separate invasions of Vietnam,

each of them resulting in failure. In the year 1128 for instance, he led a

huge army of 20,000 soldiers against the Viet people, but his

great army was decisively defeated and the king only just made it back to

Angkor alive.

Not to be deterred, Suryavarman tried again in the year 1145,

this time invading Champa. He had slightly better luck;

he managed to defeat its king and sacked its capital of Vijaya.

But as the Americans found out in the 20th century,

Vietnam is a difficult country to hold. The puppet king that Suryavarman

installed lasted only about five years. He was ousted by Cham

rebellions and when Suryavarman marched back into

Champa to support him, his army was badly beaten by the rebels.

Although the inscriptions are understandably quiet on the subject,

it's thought that Suryavarman himself may have died on this expedition,

but whether from disease, a failed battle, or an enemy ambush,

is unclear. All of this warring for little benefit

must have drained the coffers of the Khmer state and caused great instability

and resentment within the kingdom. Perhaps most devastatingly of all,

Suryavarman died without a clear heir. Civil wars were a constant problem

in medieval Cambodia. Of all the 27 rulers of Angkor, only 16

ever had a legitimate claim to power. After Suryavarman died, one of his

cousins seized the throne and a bitter period of fighting began.

Now, increasingly inept rulers vyed for control of the weakened Khmer state,

and it was amid all of this that the great temple of Angkor Wat was finally

completed, years after Suryavarman died.

Today, its architectural magnificence has cemented his place in history

as one of Cambodia's great kings, but it's a reputation that perhaps

he didn't entirely deserve.

Civil wars, rebellions, and foreign invasions

further weakened the Khmer state over the next 30 years

until it began to seem like its collapse was imminent.

But in the year 1120, a prince was born who would change its fortunes for the

better, a man who would be remembered as the

greatest of all Khmer kings, and the incredible story of his rise to

power should tell you just a little about what

kind of man he was.

This prince was called Jayavarman, a popular name for Khmer princes,

much as Henry was for English royalty. Since Jayavarman II founded the empire

and crowned himself the first god king, there had been a further four King

Jayavarmans, but despite this common name, there was

something very unusual about this Jayavarman. Unlike previous Hindu princes

of Angkor, he was a devout Buddhist.

From the various sculptors that depict him, we get an impression of Jayavarman

as a man with a broad, strong body, and a large head

covered with close-cropped hair. His eyes are always closed in the

statues, a half-smile of peaceful contemplation on his lips,

but his broad jaw is also set in an expression

of fierce determination.

This Prince Jayavarman was the heir to the throne of Angkor.

When his father died in the year 1160, Jayavarman,

at the age of 40, prepared to ascend the throne.

But before he could, a rival brother made a competing claim to the crown,

as so often happened in Cambodian society.

This was a clear declaration of civil war,

but Jayavarman's Buddhist faith forbade him from shedding blood,

and to shed the blood of a brother was even more unthinkable

to him. So, instead of fighting, he gave up the crown and went into

voluntary exile in the land of Champa, the traditional enemy of the Khmer in

southern Vietnam. He would remain there for five years,

watching from afar as his home kingdom descended into chaos.

That's because Jayavarman's treacherous brother turned out to be a poor sort of

king; he mismanaged the country, suffered from

rebellions, and soon faced a violent revolt from a

bold rebel leader named Tribhuvanāditya.

Astonishingly, Jayavarman seems to have forgiven his

brother for betraying him. When he heard he was in danger,

Jayavarman rushed out of exile to stand by his brother's side,

but he was too late. By the time he arrived back in the

capital of Angkor, he found his brother dead and the rebel

chief Tribhuvanāditya sitting on the throne. Once again, Jayavarman's religion

prevented him from fighting, and so he fled back to his exile in

Champa to mourn the brother who had betrayed

him.

But the rebel chief Tribhuvanāditya would have just as much luck as Jayavarman's

brother. He ruled for ten years, but he was

belligerent and difficult. He, too, faced rebellions, and soon

his insulting manner drove the kingdom of Champa

to invade. Jayavarman, in his exile, must have watched the Cham

armies leaving for war, the divisions of spearmen with their

bright shields, the trumpeting of the war elephants, the

long ships driven by oarsmen leaving the port of Vijaya.

By this time, the Khmer Empire had been weakened by decades of internal fighting.

The Cham armies were able to rampage through the Khmer lands

and easily defeat its army in battle, but the rebel King Tribhuvanāditya still

felt secure, holed up in the great capital of Angkor,

behind its ring of tall walls. That was, until the true strength

of the Cham people came into its own. Their experience as

maritime traders meant that the Cham were skilled sailors.

They amassed a great fleet and sailed it up the Mekong River,

across the lake Tonle Sap, and directly into the heart

of the Khmer capital. It was a daring surprise attack,

and when the rebel king saw those ships with their dragon-headed prows

and bright umbrellas massing on the lake in their hundreds,

he must have known that all was lost.

The Cham army burned the city of Angkor to the ground.

They destroyed its temples and palaces, and set fire to the wooden houses of its

people, leaving it a smoking and desolate waste.

They executed the rebel chief Tribhuvanāditya

and anarchy descended upon the lands of the Khmer.

Still in exile in the kingdom of Champa, and now an old man of over 50 years,

the exiled prince Jayavarman heard about what had happened

with what must have been a heavy heart. He knew that he had to return home to

help his people. When he crossed the border, he must have

ridden through a devastated land full of burned villages and hungry

people, but his moment of destiny had finally

arrived. He returned to the capital city he had

fled so many years ago and the people there greeted him as

their king, crowning him Jayavarman VII.

So, the pacifist Jayavarman became the King of Angkor in the year 1181

without ever having shed a drop of blood. But as he sat on the throne in the

capital, Jayavarman could still smell the smoke in the air.

Angkor's buildings were burned and the bodies of its people

still lay in the streets. The armies of Champa

still rampaged through his land, burning villages, and terrorizing his people

who now looked to him for protection. Perhaps it was this newfound

responsibility that brought Jayavarman's Buddhist pacifism

to an end.

He ordered a great army to be gathered and marched out to meet the rampaging

invaders on the battlefield. He was successful and scored victory

after victory as he drove the invaders from his lands.

Once the Cham armies were expelled, Jayavarman VII

rode back to Champa, this time not as a broken exile, but at the head of an

army. He took revenge on the Cham people for the destruction of Angkor,

sacking their capital in turn and dethroning their king.

Cham finally became a part of the Khmer Empire,

which was now wider and broader than it had ever been in history.

But when Jayavarman returned to his capital, he found it still in a state of

great destruction. Its wooden houses were burnt, its gilded

temples robbed, and its once opulent palace lying in ash

and ruin. So, he embarked on a building project that would have

few equals in history, and would turn the capital of the Khmer Empire

into the envy of the world. Jayavarman rebuilt the city in a single

burst of vast constructive energy, and this

part of Angkor is known today as Angkor Thom, or the Great City.

Jayavarman's new city was a perfect square of mathematical precision,

surrounded by a moat three kilometers long on either side,

and enclosing an area of nine square kilometers.

You really have to see aerial photographs to get a sense of the

engineering marvel that this city represents.

Jayavarman VII poured all of his energy into the construction of this new

capital, and one inscription found in the city

even refers to Jayavarman as a groom, while the new city of Angkor Thom is his

bride. Carvings in the Bayon temple in Angkor

Thom give us a glimpse of the frenzy of construction that went on here.

The city must have been wrapped in bamboo scaffolding as far as the eye

could see, with the sounds of hammers and chisels

napping away at the stones, the huffing of work elephants carrying

their loads of stone through the streets, and workers heaving

on ropes.

Jayavarman undertook a vast public works program

too, building roads that connected every one of Cambodia's towns.

The building project swelled the population of Angkor

and supercharged the kingdom's economic growth,

but Jayavarman would be significant for one other reason.

He was not the first Buddhist king of Cambodia, but he was the first to declare

Buddhism the state religion, and from the moment

of his coronation, he embarked on a programme to convert

Angkor's society from their Indianized Hindu culture.

Before the year 1200, art in the temples of Angkor mostly portrayed scenes from

the Hindu pantheon such as Vishnu reclining on a lotus leaf,

or the churning of the primeval sea of milk

in Hindu creation stories. After the year 1200, scenes from the

Buddhist folk tales called the Jatakas and scenes from the life of the Buddha

began to appear on the temples instead. The great temple of Angkor Wat was

slowly transformed into a center of worship,

not for the Hindu god Vishnu as it was designed, but for the Buddha.

It amounted to a non-violent revolution that pervaded every level of Khmer

society.

Buddhism had always been a part of medieval Cambodia.

As we've already seen, it was popular among commoners

but it had virtually no traction among the lords and nobles of high society

who were devoted to Hinduism and the Indian way of life.

You can think of Buddhism in Cambodia as something like Christianity during the

first and second centuries in the Roman Empire; when a liberal and tolerant ruler

held power, its followers could go about more or

less unmolested, but it took only one tyrant for things

to get unpleasant. But now, just as Christianity had in Rome,

Buddhists began to take over the culture that had once persecuted them.

Buddhism succeeded in Cambodia because it was inclusive and universal in its

outreach. It recruited its disciples and monks not

only from the nobles and royal court, but also from the villages and among the

peasants. This inclusiveness was also reflected in

its architecture. King Jayavarman VII had an enormous

temple built in Angkor Thom called the Bayon.

In line with Buddhist ideals, it was the first temple in Cambodia to be built

without any walls, indicating its openness to all of

Angkor's people. But the kingdom's conversion to Buddhism

would have wide-reaching consequences that Jayavarman may not have

anticipated. As a Buddhist, he renounced the title of

god-king, instead giving himself the humble title

'the lord who looks down'. But he still retained religious

authority in the kingdom and presided over the construction of

temples and image houses.

This was possible because Jayavarman was a Mahayana Buddhist,

a branch of Buddhism that was highly malleable and adaptive.

As it spread north out of India into Cambodia, Tibet, and China,

Mahayana Buddhism took on local customs and beliefs wherever it went.

So, it was no problem for Jayavarman to retain the traditional religious power

of the god-kings who had come before him. But in the century that followed

Jayavarman's rule, the state religion would change multiple

times, depending on the varying beliefs of the

ruler. The Khmer Empire would be Buddhist for

one king's reign and then return to the Hindu god-kings

for another, and this inconsistency seems to have led

to a widespread collapse in the trust that the Khmer people put in their state

religion. The common people must have asked

themselves 'well, is the king a god or isn't he?'

Into this vacuum of trust swept a new religion.

It was a hard-line branch of Buddhism called Theravada,

which held much closer to the way Buddhism was originally taught

in its homeland of India. Theravada Buddhism

is austere and uncompromising. Its monks live in poverty,

forbidden from even touching money. They wandered between villages on

pilgrimage and lived only on what the people gave

them to eat.

For centuries now, Khmer society had been a picture of inequality;

Khmer peasants paid punishing taxes to the temples,

did back-breaking labor in the fields, and could be conscripted

into vast work gangs whenever a new temple, reservoir, or royal mausoleum was

built. It's estimated that the construction of

the great reservoir of the West Baray, for instance,

would have taken the work of 200,000 peasants

working for three years. Meanwhile, the king and his nobles, as well as the

priests and holy men in the temples, lived in luxury. The king's palace

required the services of up to 4,000 palace women, for instance.

While according to the inscriptions at just one medium-sized temple,

it required a staff of a thousand administrators,

600 dancers, 95 professors, and a whole host of other staff

amounting to nearly 13,000 people,

and all of this opulence came at the expense of the peasants.

But all this promised to come to an end with the spread

of Theravada Buddhism. This new breed of Buddhist priests lived

in grass huts among the villages rather than in golden temples.

It's not hard to see how this new religion became so popular among

Cambodia's people, and how dangerous it would soon become

for the authority of the crown.

By the year 1295, only 70 years after Jayavarman VII's death,

the spread of Theravada Buddhism meant that the king was no longer considered

to have any religious authority. The reign of the

god-kings had come to an end. For the rulers of the empire

that followed, this would spell disaster.

When Jayavarman VII died in the year 1220,

he would have been close to a hundred years old.

The mourning must have been tremendous; the pipes and conches, the drums and

gongs, and flutes that sounded at his funeral would have been audible from great

distances. The people of Angkor were mourning for

their greatest king but they may as well have been mourning

for their whole empire. That's because after the reign of

Jayavarman, the whole of Khmer society would enter into a steady but

unstoppable freefall. From this point on, all monumental

religious building projects in Angkor came to an end. Soon, virtually all

building projects ground to a halt and over the next hundred years,

the creation of stone inscriptions in the capital would slow until they

eventually disappeared forever. Frustratingly for historians,

these stone inscriptions were more or less the only source

about what was going on in this kingdom at the time.

With their ancient alphabet, the Khmer kept many books of their own,

but these texts were written on strips of dried palm leaf

which are very delicate and perishable. They had to be recopied every hundred

years or so if they were to survive and for this reason, not a single

Angkorian text has survived to this day. We have only

their inscriptions in the stone to learn from,

and with the end of stone construction in Angkor, we're left guessing

as to what exactly happened in those years.

The last recorded king of Angkor was Jayavarman IX,

who reigned for nearly a decade from 1327

to 1336, when he was supposedly killed by his head gardener

who married his daughter and took his place on the throne.

After this, there are no more records. For the next 200 years, not even the name

of one king has survived. This period is known as the Dark Ages of

Cambodia. The next thing we hear about the

city of Angkor is the report of those Portuguese explorers

who opened this episode, stumbling across the ruins of the city

deep in the jungle. But what happened in those dark 200

years when the Cambodian inscriptions came to

a stop? What fate befell this great empire that

had once been one of the world's mightiest powers?

How did the world's largest city turn

into nothing more than a string of scattered ruins?

In the year 1296, the Mongol Emperor Timur Khan, who sat on the dragon throne

of China, sent an ambassador to their southern

neighbor, the Khmer Empire. One member of this mission

was a man named Zho Daguan who spent a year in Angkor. When he returned to China,

Zho Daguan wrote a long report for the emperor

on what he had seen of the society and culture of Cambodia.

This document has survived to this day and it forms

one of the most crucial pieces of testimony about what life was like

in medieval Angkor towards its end.

Zho was particularly struck by the architecture of the Khmer capital.

All official buildings and homes of the aristocracy,

including the Royal Palace, face the east. The Royal Palace stands north of the

Golden Tower and the Bridge of Gold. It is one and

a half mile in circumference. Other dwellings are covered with yellow-

-colored pottery tiles. Carved or painted Buddhas

decorate all the immense columns and lintels. The roofs

are impressive too. Open corridors and long colonnades arranged in

harmonious patterns stretch away on all sides.

Zho Daguan also noticed the large numbers of Theravada Buddhist monks

walking the streets. After nearly a century of growing

influence, the Khmer King Indravarman III had finally made the austere religion of

Theravada the official state religion but despite

this, it seems that the pomp and magnificence

of the Khmer kings hadn't dimmed in the slightest.

When the king goes out, troops march at the head of his escort,

then come flocks, banners, and music. Palace women, three to five hundred of

them, wearing flowered cloth with flowers in their hair, hold candles

in the hands bearing royal treasure of gold

and silver. Carts drawn by goats and horses,

all in gold, come next. Behind them comes the sovereign

standing on an elephant, holding his sacred sword

in his hand. It's clear from Zho's notes that despite the most

austere form of Buddhism taking over the country,

the inequalities of Cambodian society were still rife.

Only the ruler can dress in cloth with an all-over floral design.

Around his neck, he wears about three pounds of big pearls.

At wrists, ankles, and fingers, he has gold bracelets

and rings all set with cat's eyes. Meanwhile, the common people dressed

plainly. From the king down, the men and women

all wear their hair wound up in top-knots,

and go naked to the waist, wrapped only in a cloth.

But alongside this remaining royal extravagance,

there were signs of extreme stress already beginning to show beneath the

surface of Angkor's society. By this time, the golden age of the Khmer

was passed. Jayavarman VII had been dead for almost

100 years, and it's clear that the empire had begun

to slide into decline.

Part of the reason for this was due to the rise of powerful enemies in the

region. Both the Vietnamese and Thai people had

grown in strength and confidence around this time

and were beginning to put pressure on the Khmer lands.

Zho Daguan mentions this at one point in his testimony.

In the recent war with the Siamese, the country was utterly devastated.

These Siamese were the kingdom of Ayutthaya,

in what is now known as Thailand. Ayutthaya was once part of the Khmer

Empire, but it had broken free in recent

centuries. Now, it was a rising power in the region,

a trading kingdom with a vast port capital that swelled

with the wealth of trade in the Gulf of Thailand.

When early French explorers visited Ayutthaya,

they would compare it to Paris in terms of its size and wealth.

By this time, the Thai were beginning to exert influence in the region,

conquering northern kingdoms and city-states,

and by the year 1350, Ayutthaya had gained enough confidence to start

challenging the great power of the region

in open battle. From this point on, for a period of a hundred years or so,

wars between the Thai and the Khmer were incessant and mostly one-sided.

The Khmer lost several large and profitable territories on their borders

which weakened them and further reduced their ability to defend themselves.

As the mid-14th century neared, the Thai people felt bold enough

to invade the Khmer heartland and take a swipe

at the great capital itself.

In 1352, the Thai King Uthong marched a great army into Cambodia and

encircled the city of Angkor.

While Angkor was large and had sections surrounded by strong walls,

it was not a defensible stronghold. It sits in the west of Cambodia, and

while attacks were mostly coming from Champa

and Dai Viet in the east, this was in a strong position, but now

attacks were coming from the west and Angkor began to look increasingly

vulnerable. The very features that made Angkor

perfect for rice farming, its wide flat plains, made it a difficult

city to defend in times of war. Some historians have also argued that

the extensive system of roads built by Jayavarman VII, which had

boosted the empire's economy for over a hundred years, would now work

against it. On these well-maintained roads, its

enemies could now march across Cambodia at great speed, and since the

road network was so dispersed, the only defensible choke point in the

country was at the gates of the city, and by the time the enemy had reached

there, it would have been too late.

King Uthong's siege succeeded. The walls of Angkor

fell, its defenders were overcome, and the Thai

soldiers swept into the city and toppled its king.

For a period, Angkor was ruled by a series of puppet kings

loyal to the Thai, but the Khmer, as always,

were a proud people and refused to accept foreign rule.

They rebelled again and again, with a Khmer king

finally retaking the throne. This was until the final siege of Angkor in

the year 1431. The final siege lasted for seven months,

and the Khmer resistance must have been terrific,

but the Thai armies completely encircled Angkor,

cutting off its supplies on the land and blocking the canals.

We can imagine the drums of war beating and the trumpeting of the elephants,

the smoke rising from the siege camps as the city of Angkor

was slowly throttled of life. After seven long months, the city

surrendered and the Thai forces sacked it completely,

looting it of all its valuables. Statues from Angkor have been found

decorating the ancient Thai capital of Ayutthaya,

suggesting an organized campaign to loot and despoil the city

that was once the Rome of this region.

The Thai conquerors put one of their own princes on the throne of Angkor,

but they never conquered the whole land of Cambodia.

Once again, the usurper sat on the throne for only a short time

before a Khmer prince chased him away and reclaimed the crown.

But after this humiliation, it was clear that Khmer kings

could no longer rule from the great city of Angkor.

They moved the king and his court south to a more defensible location

around where Phnom Penh, the modern Cambodian capital, is today.

It was the end of the great golden era of the Khmer Empire,

and for the city of Angkor, it was the first step

in its gradual but inescapable collapse.

It's worth noting at this point that Angkor had recovered from the

destruction of war in the past. In fact, some of its greatest

architectural achievements had risen out of the ashes of destruction,

such as Angkor Thom in the time of Jayavarman VII.

This shift of administrative power to the south

doesn't seem to explain the wholesale abandonment of the entire city,

so what happened?

Many explanations have been given for the abandonment of Angkor;

some historians have argued that only a cataclysm

like a great earthquake or the arrival of bubonic plague

can account for the disappearance of such a vast population,

but because of the scarcity of inscriptions through the Cambodian Dark

Ages, we're left with only the archaeological

record to go by. Recent evidence suggests that

Angkor's decline was not a thunderclap. It didn't happen all at

once, and there is little evidence of a mass

die-off of people. New scientific evidence shows that the

intensity of land-use in the centre of the city

had declined gradually for more than a hundred years before its supposed

collapse. Analysis of sediment cores shows that in

the first decades of the 14th century, tree growth increased in the region

while signs of soil erosion and burning all declined, pointing to a reduction in

human activity. By the end of the 14th century, Angkor's

moat was covered in a floating mat of swamp

vegetation, indicating that it was no longer being

maintained.

As with the collapse of many civilizations we've looked at already,

it seems that climate was to play a large part

in the demise of Angkor. Recent research by Australian

archaeologists suggests that the decline may have been caused

at least in part by the global transition from the Medieval Warm Period

to the Little Ice Age, a shift that we saw

in the previous episode had devastating effects for the Vikings of Greenland.

But in Cambodia, with the complex mechanics of its monsoon season,

this period of climate change seems to have had

somewhat contradictory effects. If we look at the enormous canals to the

south of Angkor, we see that around this time, they became

filled with a large amount of coarse- -grained sand.

This suggests a period of torrential rainfall and flooding,

during which silt deposits were swept down from the hills in large amounts.

But around the same time, the exit channels that usually drained water from

the large reservoirs were deliberately blocked while others

were turned into inlets to increase the water flowing into the

lakes. This all seems to indicate a period of

drought, when the citizens were fighting to keep

the reservoir levels high, so which was it, droughts or floods?

This apparent paradox has puzzled archaeologists for many years,

but an answer came in the recent publication of a study

into the widths of tree rings in Cambodia, covering a period

of nearly a thousand years. Tree rings are wider

in periods of heavy rainfall and thinner in years of low

rainfall. This study shows that after the year 1350, monsoon

rainfall in Southeast Asia became incredibly variable.

Between the years 1330 and 1375, a 25-year period of severe droughts

occurred, and this happened again between 1400 and

1425. Between these extreme dry periods, the

rains fell in a deluge. The period from the mid-14th

to the mid-15th century contains an astonishing number of both

the wettest and the driest years of the last millennium,

and this would spell doom for the city of Angkor.

The Khmer were well-prepared for droughts that lasted one or two years,

but a nearly 30-year drought would have caused immense damage

to this primarily agricultural economy. The people must have decided that

their water system needed to adapt; they hurriedly built

emergency canals running from the hills directly to the

city, long and straight so that more water

could flow into the reservoirs and fields.

They might have celebrated, having solved the problem, as they had learned to do

over the centuries, but when the drought came to an end,

the rains that year were deluge of unexpected

force and volume. There would have been little time to react

before the water rushed down from the hills and the entire system was

overwhelmed. The emergency inlets that had increased

water flow during the drought would now become the city's downfall.

Water would rush down them in greater volumes than the city

was designed to withstand and the reservoir would fill to bursting.

The Khmer may have made some attempts to drain their tanks,

desperately digging emergency outlets and trying to block the canals they had

built only years before, but it would do no good. The reservoirs

began to overflow.

It must have been a terrifying sight as the water began to pour

down the sides of the banks, flooding into the city,

turning streets into rivers, and sweeping away the fragile wooden houses

in a torrential flood of water. The people of Angkor would once again

work to re-engineer their enormous water system

back to its previous state. They blocked the new inlet canals

and widened the outlets to drain the reservoir,

and just when they had finished, the drought would return

and the whole cycle would begin again.

This repeated cycle of severe drought and flooding

seems to have been a stress that Angkor's water system

simply wasn't versatile enough to withstand,

and it led to a series of cascading failures.

A cascading failure can occur in any system of interconnected parts

when one part of the system fails. Other pieces of the system must now

compensate and this in turn overloads them.

Nodes throughout the system fail one after another

until the whole infrastructure grinds to a halt.

One bridge leading into the temple complex of Angkor Thom

tells a chilling story of what must have happened during that time.

The first thing we notice is that this bridge appears to have been hastily

constructed, with none of the refinement of the

nearby constructions, and when we look closer we see that it

was built out of building material recycled from nearby temples.

Some of its stones show the intricate carvings of a temple wall,

but mismatched and jumbled in this new structure.

The fact that the Khmer people had to hastily build this bridge shows that

something had gone terribly wrong with their water control system,

and the fact that they had to reuse stones from their most sacred and

revered buildings shows that the situation was desperate.

Judging by the damage done to the bridge, efforts to control the floodwaters

were unsuccessful. In the end, the river that was supposed to run under

it carved away around the bridge and its eastern end collapsed. But one

question remains; did the people of Angkor leave because

the infrastructure failed, or did the infrastructure fail because

people had already left? We may never know the answer to this

question, but I would argue that a feedback loop

exists between these two factors. A vicious cycle came into play as Angkor

diminished in relevance. As this happened, fewer resources were

spent maintaining its vast and complex water system,

and the cycle of drought and flooding finally broke it completely.

As larger parts of the city flooded, sewage and sanitation systems

such as they existed would have failed, and diseases like dysentery and cholera

would have spread among the flooded streets.

As water in some areas stopped flowing and became stagnant,

mosquito populations may have thrived in the still pools

and cases of malaria would have increased.

As has happened with other dying cities around the world,

words may have got around that the city was cursed,

that devils lived there that caused disease,

and now ever-fewer resources would be spent

maintaining the water systems of a dying city.

The enormous amount of maintenance required in the water system

meant that Angkor essentially had a minimum possible population.

Below the certain number of people required to maintain it,

the system would have failed utterly. The city would have flooded permanently,

and life there would have become unlivable.

Now, only monkeys would clamber among the temple roofs,

and the jungle would amass outside the city walls like an invading army,

ready to reclaim its streets and palaces. Soon saplings, shrubs, and wild grasses

would burst through the once opulent streets.

Since few valuables or artifacts have ever been uncovered in Angkor,

it's likely that looters scoured the ruins too,

stripping them of anything of value. Most buildings in Angkor were wooden and

thatched with palm leaf; as the first years and decades passed,

these disintegrated quickly and left few traces. But the stone

buildings remained. Someone entering the city of Angkor in the later half of the

15th century, a scavenger or a fisherman on his way to

the great lake, would likely have found streets still

flooded by the bursting of the city's water works,

now overgrown with lilies and lotuses, and covered by the shade of the jungle

canopy. The writer Malcolm Macdonald described

the eerie quiet of these ruins after his visits in the 1950s.

Daylight is filtered through many thicknesses

of green foliage and has a mysterious, eerie quality. It is half-light

and half-darkness, a greenish twilight,

a lifeless, haunted sort of illumination such as might glimmer in a ghostly

underworld. Those stone buildings still standing

would soon become wreathed in vines and creepers.

Where once vast crowds of people had gathered to watch royal processions,

now the only sounds were the chirping of parakeets and the movements of monkeys

in the trees. The stone arches of the city's palaces

became home to bats and owls, and already

the species of tree that we most readily associate with the ruins of Angkor

would have begun its steady conquest of these crumbling ruins.

The banyan tree is an endophyte, the closest you can get to a predator

in the plant world. It lives by devouring other trees. The tiny red seeds of the

banyan are eaten by birds and then deposited in

their droppings. Banyan seeds that fall on the ground

usually die, but when they land on another tree, they

put down roots into its bark. From that point on, the banyan grows

swiftly and the fate of the host tree is sealed.

Banyans put down hanging roots that reach to the ground

and then wrap themselves around the unfortunate host,

growing to cover it completely and eventually strangling the life out of it

like a boa constrictor. The host tree dies and decomposes,

and soon only the banyan remains, with a hollow space in the tree's center

where the unfortunate host once stood. But banyans are just as happy growing

on our human construction as on a host tree.

For this reason, removing sprouting banyan saplings from buildings

is still an important part of building maintenance in countries like Cambodia

and Sri Lanka today, much as it was in the time of the ancient Khmer.

But in Angkor, there was no longer anyone left to do this.

Soon after its abandonment, the seeds of the banyan

would begin to fall on its abandoned temples and palaces.

They would sprout and soon put down their hanging roots like bunches of hair

which then swell and harden into woody trunks.

If you watched a time lapse video of this, it would look like some science

fiction monster wrapping its tentacles around the stones.

The banyans slowly enveloped the temples and palaces,

crushing stone walls beneath their weight, driving roots between

stones, cracking pillars like twigs.

Today, these banyan trees form some of the most iconic sights of the ruins of

Angkor, draped over them like the arms of some

tentacled creature intent on devouring the works of these

ancient walls. Today,

when we visit the ruins of Angkor, it reminds us of the dangers

of the challenges our own societies face. They remind us of the threat that

growing inequality poses as the rich become richer and the poor

become poorer around the world. It also shows us the dangers posed by a

global climate that has become increasingly variable

and unpredictable. We may hope that our systems are robust

enough to withstand whatever the global climate throws at us

in the next century, but as the example of Angkor shows, this

may not be something that we are able to take for granted.

I want to end the episode by listening to a piece of music

we've heard a few times already. It's an ancient Cambodian epic

called the Reamker, performed by dancers in Cambodia.

It's the Khmer version of the Hindu epic the Ramayana,

but a man called Rama whose wife is stolen from him by a demon king.

It's a song of loss and love that sings down to us through the millennia

and is still being performed in Cambodia today.

As you listen, try to imagine what it must have been like to live

in that vast and ancient city of golden towers

as its age of glory came to an end.

Try to imagine what it must have felt like to live in a time

when the great machinery of water control built by your ancestors

was beginning to fail and people are leaving the city

in droves. As streets emptied and markets closed, as the monks left the temples,

and the fires in the rest stops began to go out.

Imagine being one of the last people to live in the city of Angkor,

watching the sun set over the grand temples

that are already beginning to crumble against the skyline,

sprouting with their first banyan saplings

as the cries of the parakeets and the monkeys

sound in the growing darkness.

Thank you once again for listening to The Fall of Civilization's Podcast.

I'd like to thank my voice actors for this episode; Rhy Brignell,

Lou Millington, and Sebastian Garbatch. I love to hear your thoughts and

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