[narrator] Summer, 1492. After three months at sea, the Santa Maria, the Pinta and the Niña anchor off the Bahamas. Europe has discovered the Americas. What happens next? Conquest and colonization by settlers who remake America in their image. They advanced, and destroyed. But there is another story, about the animals and plants they brought here. [rumbling] And what they found here. And how the Americas were completely transformed. It all began 500 years ago. [narrator] Christopher Columbus left his home in Italy to fight for his vision. He aimed to sail west, to the riches of Asia. This is an era of discovery and lust for expansion, and it all began with the ambition of a queen. [knocking on door] In Europe, the nobles have grown wealthy by trading with the East. Spices and gold, gemstones and silk are the most lucrative goods. But Europeans have lost the Silk Road to the Turks, and foreign trade is in decline. The wealth of kings is in danger. Isabella, queen of Spain, is desperate to find new routes to India. And she has a plan. -[speaking Spanish] -[interpreter] Let him in! [narrator] This is the most powerful woman in Europe. A continent of expanding horizons, filled with competitive and inventive souls. For 500 years, they have been building: castles, palaces, centres of trade. Kings and popes have raised armies to fight each other and their enemies on Europe's borders. Nowhere else are rivalries so intense, gold fever so widespread, religious fervour and business expertise as tightly wound, as in Europe in 1491. Ideas are advancing. Curiosity and the thirst for power push Europe's limits. [wind whistling] They're seeking riches and land, heading towards the frontiers of their world. But no one can guess that far beyond the end of that world, lies another, of which they know nothing. The Amazon is a crowded place. The Andes cradle a vast empire ruled by powerful god kings. Mesoamerica may be the most densely populated place on Earth, home to the most imposing civilizations on the continent. And the Atlantic coast is filled with villages and fields. Along the rivers, great cities are built around monumental plazas and giant earthen mounds. It is an ancient world, inhabited by hunters and gatherers, fishermen and farmers, kings, slaves and soldiers. Down amongst the trees, where the Missouri, Illinois and Mississippi rivers merge, in what is today the state of Illinois, lies one of the most fertile zones of North America. It's home to one of the largest civilizations in the continent. The Mississippians: mound builders from the Great Lakes to Florida. Flourishing in the year 1150. The first explorers thought these great mounds were natural, carved by retreating glaciers. Now we know that they were the centrepieces of cities. Cities like Cahokia. Busy trading posts of earth and wood, with populations of thousands of people. No one knows what they called themselves or what language they spoke. But we do know why they were successful. The Mississippians are farmers. Their staple crop is fuel for the ever-growing population. It is a plant native to the Americas, unknown to the rest of the world. [rustling] Once they learned to grow it, they could stay in one place. This simple diet translated straight into the energy to build a civilization. But corn is not a blessing from nature, nor a gift of the gods. This crop is the outcome of man's first feat of selective breeding. Scientists realized relatively recently that the ability to grow corn is a key to high cultures in the Americas. [man] The staple crop in North America was corn. Six thousand years ago, ears of corn were only about as long as a person's thumb and they were barely edible. It took thousands of years to develop a more nourishing and larger hybrid, and also a hybrid that could grow in cooler climates outside of Mesoamerica. And it wasn't until about 1,100 years ago that corn reached the Mississippi River Valley. [narrator] Corn is the result of the domestication of the wild teosinte grass. Early Americans started with this spindly stalk... and over the centuries they developed it into today's giant cob. Archaeologists and biologists are still debating how corn was achieved out of a tiny Mexican wild grass. Corn is one of the keys to understanding American civilization. Wherever it flourishes, so do great cultures. Yet the greatest American empire of them all is found where corn cannot grow: high in the Andes. The Inca Empire stretches nearly 2,500 miles down the west coast of South America. Incas build palaces, storehouses and castles in the towering mountains. In their realm of six million people, they rely on manpower to transport stones. They have neither beasts of burden nor the wheel. And the energy for that is provided by another amazing foodstuff. Incas are famed for their gold, but their true treasure is less glamorous. A tuber native to America and unknown in Europe. Cultivated here 8,000 years ago, in the region around Lake Titicaca, in today's Peru and Bolivia, at an altitude of 4,000 meters. What is now a staple food in Europe was a South American invention. By the year 1491, the Inca grow hundreds of varieties, domesticated from wild ancestors. Some poisonous, some even carnivorous. A thousand years ago, in one city alone, 30,000 tons of potatoes were produced every year. They preserved the tubers by mashing them into a substance called "chuño." After harvest, potatoes are spread on straw and left out to freeze at night. During the day they are exposed to the sun. [speaking Quechuan] Trampling them eliminates water and allows them to dry. Chuño can be stored for ten years, an excellent insurance against possible crop failures. The Inca carved step-like terraces into the mountainsides to stop the soil eroding and create a flat surface for their crops. Terraces absorb more sunlight than steep slopes, so potatoes can grow at the highest altitudes. And all this is achieved by manpower alone, using wooden tools. In North and South America in 1491, farmers grow corn and potatoes for a hundred million people. [speaking Quechuan] There's another continent across the ocean where a hundred million more people survive, growing very different food in a very different way. In this same year of 1491, Europeans have to grow food for a similar number of people in one-tenth of the space. Europe is a busy and crowded continent. People here lack land. And what they work on is not even theirs. [farmer muttering] [narrator] Most of them are farmers. Europe is filled with fields owned by the nobles or the church, tilled by peasants. [farmer muttering] [narrator] Their main diet is bread and porridge, both made from grains. They plant rye or wheat in winter, oats or barley in the spring. And every third year, the field lies fallow to regenerate. They know how to use wind and water for power. It is heavier work, with higher yields in a smaller space. It is an agricultural revolution and it allows the European population to thrive. [blades creaking] And for that, one more element is essential. [man speaking German] [speaking German] [interpreter] You see, old European agriculture was based on grains: wheat, rye; while old American agriculture was based on corn. But another difference is even more important. European agriculture originated in a combination of farming and raising livestock. That was not the case in America. That gave European agriculture a great advantage. First, the fertility of the soil was renewed through cow dung, and secondly, the livestock needed pastures and that protected ecological reserves. [narrator] Domesticated animals. They make all the difference. [bellows] America has no cattle, no horses or pigs, no sheep, mules, goats or hens. European horses are beasts of burden. They can pull ploughs. And cattle provide meat, fur and hides. The domestic pig is a chief source of meat and leather. [sniffs] Like the sheep, that needs no stable and finds its own food. Even a mule can pull a cart. And cows give them milk, butter and cheese. Europeans are breeding ever more productive animals. But it's not only people that domesticate animals. By 1491, the big five-- horses, cattle, goats, pigs and sheep-- have domesticated the European landscape. They are essential to Europe's prosperity. And none of these are known to North or South America. For Inca farmers in the Andes, their chief source of transport and meat is the llama. This is the biggest domestic mammal in the Americas. The llamas also offer dung for the soil and hides for clothes. But you can't milk or ride them, and the animals can't pull a plough. So they are no good for fighting or for traveling. -[llama braying] -But their wool is one of the best gifts. It's warmer and lighter than sheep's wool and produces a greater yield. [llama braying] [speaking Quechuan] They use bronze knifes to shear them. The second principal domesticated animal of the Americas is even smaller. For the Aztecs, in today's Mexico and Guatemala, the turkey is so important that they dedicated two religious festivals to it. [chirping] Native Americans have so few domesticated animals because the biggest native mammals in the Americas have long since died out. At the end of the last Ice Age, the megafauna in the Americas, the giant bison and the mastodons, went extinct, and the reasons for that are probably two-fold. First of all, as the Ice Age was ending, the climate became much hotter and drier, and this killed the vegetation that these very large animals depended on. Secondly, the arrival of hunters into North America crossed over the Bering Strait land bridge from Asia coincided with the extinction of these animals, and very likely these hunters went after these large animals who were slow and had a lot of meat. What this left in North America were animals such as bison, deer and antelope that are not suited to domestication. [narrator] The animals that remain have one thing in abundance. Space. From the glaciers of the Arctic north to the great plains of today's Midwest, gigantic herds thunder across North America in search of food. There is room for antelopes... and for caribou. And there is room for bison. Room for the giant grizzly. And in the sky above, for flocks of birds that block out the sun. Billions of passenger pigeons, ducks, and geese from horizon to horizon. In 1491, they are hunted. By hundreds of Native American tribes. Village dwellers in the forests of the northeast, and nomads on the Plains. These civilizations develop new methods to guarantee their meat supply. They can't domesticate these animals, so they find a way of making their prey come to them. When they notice that grass grows better after being burnt by lightning strikes, they start to burn the prairies themselves. Many tribes such as the Sioux, Cheyenne, Comanche, Shoshone or Blackfoot burn the Central Plains and the prairies to increase their spread. [fire bow squeaking] Burning the undergrowth in the fall keeps the forest open and park-like and makes hunting easier. Burning the prairie creates lush grassland. And the prairies cover 20 million square kilometres. The new, rich pastures will lure and increase the numbers of herbivores, as well as the predators that feed on them. America in 1492 was not a pristine wilderness. That's a romantic myth. It was in many ways a managed landscape. Natives regularly burned the forests and the prairie in order to attract game. [bison grunts] [narrator] With this technique, nomadic Central Plains Indians even lure the biggest mammal in the Americas. They domesticate the land in order to attract wild animals. Wherever they roam, bison are the chief source of food and clothing and of tools made from their bones. [grunting] The bison thrive. By 1491, North America is home to perhaps 30 million. They reign on the prairies from Montana to Texas, pushed east by Native Americans along a path of fire, opening up forest into virgin land. The bison have gained a new habitat, far beyond their original range. [birds chirping] Native Americans have neither guns nor horses. They have to hunt on foot. They dress in hides, and they hunt with the bow and arrow or the spear, all made of wood and leather, bone and stone. [bison grunts] The bison hunt is essential for their survival. Over in Europe, hunting is not about survival. They hunt if they are noblemen, for sport, for pleasure and prestige. [panting] They have guns, but hunting is a ritual, carried out with the weapons of a knight. [boar squeals] And only the nobles are allowed to hunt. If ever they catch a peasant, he will be punished for poaching. Unlike in America, there's no room here for an abundance of wildlife, for endless herds. Wild animals are retreating into forests. In Europe the land is man-made. Agriculture and cities push the wildlife back. [cattle mooing] Untamed land is now a rarity. But they have one other major food supply. Fish should be a cheap and abundant diet for every social class in Europe. Christianity, the common religion all over Europe in 1491, approves of fish. Eating meat is banned on more than a hundred days a year. The demand for fish is huge. But there is a problem. Intensive agriculture is damaging the fish supplies. [thunder crashing] Europe's once-unlimited supplies are dwindling fast. What happened to the fish stocks in Europe? [man] As people started to grow crops and cut back the wild woods, this released huge amounts of sediment into the water courses, which changed them from being fast, clear-flowing rivers and streams into slow, turbid rivers and streams, and the freshwater fish found a problem with this. Particularly migratory species that came up from the sea to spawn in rivers, animals like salmon and sturgeon. There was another factor which also cut down the supplies of these migratory fish and that was that people started to build dams along rivers, and when that happened, the migration runs were blocked and the populations declined. [narrator] Once they had emptied and polluted their lakes and rivers, they turned to the sea. For the first time, they started intensive sea fishing. They found abundance on a scale never seen before. And they exploited it. Cod and herring from the North Sea were the first to be fished. Every five years, catches doubled. By 1300, thousands of tons of dried fish were exported from Norway to Britain alone. In the Middle Ages, the seas of Europe were very little exploited until around the 11th century, when freshwater supplies declined, and people went to the sea for the first time and they discovered very large populations of fish, animals like cod and skates and halibut and turbot. And they were able to catch as much fish, really, as they wanted. For hundreds of years after that, all the way through to the 18th and 19th century, supplies of marine fish seemed inexhaustible within Europe and we were able to obtain what we needed. But later on, towards the end of the 19th century, industrialised fishing began and we saw supplies begin to be depleted. [narrator] But this is 1491. Europe's lakes and rivers are now empty and dirty. In the Americas, fishing is not an industry. They don't need it. Fish are for the taking. Their rivers are not used for power and are not affected by farming. Native Americans transport their fish far away from the coasts and waterways, into the interior, high up into the mountains. The Incas, high in the Andes, enjoy fish from the Pacific. The Mississippians trade with communities as far away as the Great Lakes to the north and the Gulf Coast to the south. They even eat fish and seafood from the Atlantic. Here, too, there is space for abundance. The waters teem with fish and with whales, dolphins and manatees. [whale calling] Wherever Native Americans trawl their nets, they find a bounty of thousands of different species. Menhaden, channel catfish, and sheephead. They never have to take more than nature can replace. North and South America look like a primitive paradise. But it's not that simple. The greatest numbers of fish live in the Amazon, the largest river in the Americas and the most voluminous in the world. To our eyes the Amazon rainforest is an almost untouched Garden of Eden. But it was once a very different place from what we know today. When the jungle was cleared in the 20th century for agriculture, they found the remains of a sophisticated civilization that once tamed this landscape. In 1491, this area is home to thousands of people. They tend orchards with all kinds of fruits: papaya, mango, cocoa, with nuts and palms. They speak many different languages and live in many different social systems. Their tightly-packed settlements cover an area of 120,000 square kilometres. They are linked by raised causeways, bridges, and canals. Much of this is natural savanna, created by annual flooding. But they have expanded the grasslands, regularly setting huge areas on fire. By 1491, they have created an ecosystem of plant species adapted by fire that cannot exist in nature. Eventually, the jungle will reclaim it. Further north, in what is now New Mexico, it looks like no humans could ever have lived here. Today it is one of the most arid zones on the continent. The Chaco Canyon. There is no vegetation, no water, and there are no animals to be seen. And it was already like this in 1491. But once, this area looked completely different. This is the story of a civilization that developed as far as it could, used its resources as well as it could, and still declined. More than 500 years ago, the Chaco Canyon was covered with lush vegetation and forests of pine and juniper. This fertile area was home to the Anasazi. From the year 700 on, the Anasazi built the highest and largest buildings in North America. One is several stories high and has 800 rooms that overlook the majestic canyon. A thousand people lived here. They had no beasts of burden to transport materials. Thousands of felled trees were dragged down to the Chaco Canyon on men's bare backs. There is no account of their lives or of their disappearance. But environmental historians can tell us what happened... by counting tree rings and analysing rat nests. [coyote howling] Nathan English, of the University of Arizona, spends much time in the canyon looking for traces of the ancient nests. [English] Our interest in Chaco Canyon is to learn more about how the ancestral Puebloans lived. There's a number of ways we can do that: through traditional archaeology, where we dig up ruins and sites, or we can also look at what the environment was like around the ancestral Puebloans. And the way we do that is by looking at packrat middens. And each packrat midden is like a little snapshot in time of the area around the midden itself. So you could think of it like a picture. And the middens can be up to 40,000 years old in some places. And what the midden is, is the packrat makes a nest and it poops in that nest, and then it only gets its water from eating plant vegetation, so its urine is very thick and viscous. That urine seeps into the pile of poop, essentially and solidifies, almost like amber. In the meantime, the packrat is also collecting things: the plants around it, also pot shards, sometimes even corn or seeds of squash, and those macrofossils are incorporated into the midden. So we go out, we collect the midden, and then we examine the macrofossils in that midden to look at what the ecology around that midden was like at that time. [narrator] Not only do rat middens hold information, trees do too. Dendrochronologists count the rings of ancient logs to give the exact date when the very last tree was cut down for construction. The Anasazi used juniper and pine for their timber, and to make fire. Too much of it, some think. With the trees goes the soil. The forest cannot recover. Because of erosion, water drains down, creating gullies on the way. Irrigation and agriculture are no longer possible. This large population cannot feed itself anymore. But did they destroy the forests or did the forests leave them? Other scientists who've worked here have a couple of ideas of what happened to the woodlands that were around here while the ancestral Puebloans were living here. The first is that natural climate change, uh, caused the margin of the woodland to move further north and off site. The second idea is that there were a lot of people living here and they over-harvested the wood. We are on the edge of this pinion juniper woodland, and so it's really possible that natural climate change would have caused it to move back, but also we know that the people were harvesting wood for fuel and for timber, and so it's likely that a combination of the two things are what led to the loss of forests in this area. [narrator] The year 1130 rolls around. It's one of the driest of years. The Anasazi have survived previous droughts, but the population has increased greatly. And there is no suitable territory to expand into. Without rain, it's impossible to grow enough to support the population. No agriculture means no culture. The Chaco Canyon is abandoned. These ancient Americans cut down the last tree and moved on. Using stone-age tools, they helped destroy the ecological balance of a whole region. It's a myth that native Americans always lived in harmony with nature. Over in Europe they're cutting down the forests, too. But it's different for them. [crackling] Their growing population needs more food and more space to grow it and they badly need the wood. They have the tools... they have the transport... [lumberman yells] -[narrator] And they have the energy. -[whistles] But they're beginning to run out of space. And time. Only wood can help them move forward. Wood has a special meaning in 1491. [Radkau speaking German] [interpreter] The Middle Ages were the era of wood. You find it wherever you look. Wood was the most important material for building, for making tools and furniture, and for burning. It was the only fuel. There was hardly any coal. [narrator] It is an era of competition, and wars use up forests, too. Whole armies are equipped with bows of yew wood. The yew tree is almost exterminated in Europe. Armies need iron weapons, and smelting ovens burn day and night, fuelled with wood. [soldiers shouting] [narrator] At the same time, whole forests are used to satisfy another of their European cravings. For the great buildings of the age. [bangs] [narrator] The cathedrals in the cities are made of stone, yet they absorb millions of logs for their bases and frames. Larches are needed for roof supports. Solid logs of oak, alder and elm are sunk into the ground to create foundations. Wood is indispensable for pillars and ceilings, posts and roof panels, axe handles and cart wheels. European castles, cathedrals, monasteries and churches consume entire forests in Germany, France, Italy, Spain and England. But who owns the European forests? And who is making money with them? [Radkau speaking German] [interpreter] Who the forests belong to wasn't clear in the Middle Ages. No wonder that all the great social and economic struggles of those times were fought in the forests, around the forests and about the forests. The nobles were mainly interested in the forests as hunting grounds. But for the peasants, the forests were vitally important. They couldn't live without them. They needed them to graze their cattle and as wood for fuel. [narrator] In this competition for timber, those who have money make the rules. And the money is now in the cities. The richest city of all is Venice. It's built on wood, literally. Piles sunk into the mud to create the platform on which the great stone facades can float. But behind all this is banking, interest, and capitalism. The goods that are bought and sold are transported in wooden galleons. Venice has denuded the forests roundabout to build its fleet. The city's demand is insatiable. And they start to deplete the Alps. Spruce for masts, larch for planking, elm for capstans, walnut for rudders, and, most importantly, oak for hulls. When that is not enough, they cut a swathe across Europe, all the way from the Adriatic to the Baltic. The Europeans have exploited their natural resources, leaving a continent where there are no fish in their rivers and less and less timber in their forests. Their continent is crowded with people and they don't know what to do with them. Nowhere else in the world are rivalries between princes and kings as intense, curiosity and greed as widespread, and religious fervour and business expertise as tightly wound as in Europe in 1491. And for the first time, the common people have a hunger for new ideas. The printing press is invented; books take hold and literacy spreads. But where do they go from here? [warriors shouting] Where can all this raw energy be channelled? This is the time when European kings and queens send explorers beyond the horizon to expand and enhance their power. Some explorers go around Africa to find the sea route to Asia. One has the vision to sail west, to arrive in the East. He is a seaman from Genoa, a fervent amateur who has the crazy idea of sailing into the unknown, to reach India. Christopher Columbus has spent five years trying to persuade the one person who can finance his voyage. Isabella, queen of Spain, finally agrees. What does the Spanish crown have to lose? It doesn't cost much to finance three ships. Spain has so much to gain from a shortcut to India: treasures, trade and land. At first, no one wants to board his ship. Finally he drags together a motley crew of 87 men, illiterates, petty criminals, even murderers, who choose probable death at sea in preference to the gallows. Many are soldiers with nothing to do since Spain expelled the Moors just months before. Now, they are soldiers of fortune. With his band of desperados, Christopher Columbus sets sail from the port of Seville. It is the summer of 1492. He has promised the queen and his crew that they will be in India in six weeks. Columbus is the one who discovers America. But it is the people who come after him, and what they bring with them, that will transform the New World. Land! [narrator] It is October the 12, 1492, when Columbus sights land. [man as Columbus] I saw neither sheep nor goats nor any other beast. All the trees were as different from ours as day from night, and so the herbage, the rocks, and all things. [narrator] Three Spanish ships sail west for three months in search of India. Then, finally, they arrive. Eighty-seven men, among them conquistadors, pig farmers, murderers. But this is not Asia. It is an island in the Caribbean. They have no idea that they have come to a New World. The air is hot, the water is warm. They have survived the voyage and have found land for the Spanish crown and in the name of God. They are exhausted: tired but thankful. What land is this? Where are the ports, the cities, the ships and traders they expected? The natives have seen many people arrive from the sea. Other tribes, but no one like this. [speaking Arawak] They will both soon discover that this is just the beginning. Columbus and his men stay for three months in the Bahamas and have no idea that they are on the edge of two great continents... about ten times as large as Europe. From the tropical seas... to the arid deserts. It is vast. There is space. With room for every possible landscape. Stretching from the northernmost almost to the southernmost points of the globe. They will find animals and plants they have never seen before: bison on the prairie... great herds of antelope and caribou in the mountains of the north. They look as though they are living in pristine, untouched countryside. [birds squawking] But this is a managed land... by the inhabitants of America. In 1491, America is home to a hundred million people... with civilizations as varied as its landscapes. Not only hunters and gatherers, but fishermen and farmers, kings, soldiers and slaves. But the civilizations are separate from each other. There are no books, no wheels to help them communicate. They know nothing of each other. Northern tribes have never met the cultures in the canyons. And these have never seen the huge settlements along the Amazon. And all of them know nothing of Europe. It is Isabella, queen of Spain, who made Columbus's voyage possible. [knock on door] It is the year 1493, and for seven months she has been waiting for news. Upon his return he delivers a report to the queen. [parrot squawks] In a few pages, Columbus describes the paradise he has found in her name. Land to conquer, converts for Christianity, riches to exploit. And gold. In Europe no news stays local for long. Traders, armies and pilgrims carry news across the continent in weeks. Columbus's letter is translated, copied, and becomes a bestseller. Now many Europeans are aching for their share of the treasures. A few months later, in Spain, men are moving towards the ports of the Atlantic and the Mediterranean. Men who have no land and no work. They cross the barren Spanish regions that offer nothing to live off. Desperados with nothing to lose. Men in need of a job. And the queen needs them. Anyone can come along. Anyone can be a conquistador. Even a pig farmer can win glory and riches in faraway lands. [birds calling] In 1493, 17 ships arrive in the New World, on an island in the Caribbean Sea, carrying 1,200 Spaniards. Columbus's second voyage begins a stampede of Spanish exploration and conquest. Some will go south, some to the Andes, some along the Mississippi. It is the conquest of the Americas. Driven by greed, carrying weapons, and with one animal that does not exist on this continent. With the horse, the Spanish are able to annihilate whole empires in just a few decades. [soldiers shouting] Within 40 years, the Inca in the Andes fall to Pizarro. And the Aztecs in Central America to Cortez. Where, in 1491, there were towns and cities inhabited by millions of people, the Spaniards leave only ruins. And no one to manage the land. Spanish explorers invade the Americas and bring with them the horse. First brought to the Caribbean islands, these animals reproduce and spread in the New World as fast as the wind. Horses have not been seen here since the Ice Age. Now they're back. It's as though the landscape has been waiting for them. Once ashore, a few horses run wild, and a new breed evolves, which soon takes over North America: the mustang. Within 200 years, they have reached the Central Plains and the Rocky Mountains. At the end of the 18th century, the mustang makes it as far as Canada. A hundred and fifty years later, there may be seven million wild horses in North America. For the nomadic tribes like the Blackfoot, Cheyenne, Sioux, and Comanche in the Central Plains, these wild horses are a blessing. What they used to do on foot -- fighting, hunting, traveling -- they can now do on the backs of wild horses from Europe. It transforms their lives. This Old World animal becomes a symbol of their native culture. Although the horse once came from across the Atlantic, it is now an image of nomadic America. As soon as the conquistadors have control of South and Central America, one of them heads north. Hernando de Soto travels from Florida, up the Mississippi River, looking for gold. The Spaniards leave death in their wake, and something else they bring along to keep them alive. [pig squealing] As they journey through unknown jungles, the pigs help them survive. They are the perfect source of food. They don't take up much space in the boats. They look after themselves and they eat everything they can in this new continent. They're prolific little beasts. A healthy sow can give birth to ten piglets. The conquistadors leave some behind as they go, creating an ever-growing food supply for those who come after them. The pigs are the key to their survival. But to Native Americans, they are a curse. In North America, natives do not fence their fields, and their staple crop of corn is irresistible. It seems the Indians have no idea how to fight this plague of pigs. Soon European swine are eating the seeds and young shoots. [pig snorting] Only a few generations after running wild, the animal becomes very different from the typical farm pig. It grows tusks and gets bigger and aggressive. What began with a few pigs becomes a daily nightmare for the Native Americans. As well as the horse, Columbus had brought eight pigs to America on his second voyage. Within 20 years, there are 30,000 pigs on the island of Cuba alone. They multiply, conquering the Andes, the Amazon, and North America. But the Spaniard, his horse and his pig, would never have been so successful in the conquest of the New World... without a hidden passenger. It is when the Old and New Worlds touch that the American Indian meets his worst enemy, a "very black dose" for the continent. A Spanish missionary reports... [man as missionary] An epidemic broke out, a sickness of pustules. Large bumps spread on people, some were entirely covered. On the face, the head, the chest. They lay in their dwellings and sleeping places, no longer able to move or stir. The pustules caused great desolation. Very many people died of them and many starved to death. No one took care of others any longer. [narrator] Deadly diseases contaminate the entire continent. "For the natives," writes a chronicler, "they are near all dead of the smallpox. So the Lord hath cleared our title to what we possess." To this day, scientists are still working to identify these diseases, to trace their paths and count the dead. [Isenberg] Smallpox was accidentally introduced to the Americas in the 16th century. The smallpox virus is very hardy. In blankets that are used by smallpox victims, the scabs can live for weeks, carrying the virus, and smallpox can also pass from host to host onboard a transatlantic vessel until it reaches the Americas. And of course once smallpox reached the Americas, it was introduced to millions of new hosts, human hosts, who had no acquired immunities to these diseases. And so smallpox, together with measles and influenza, had a devastating impact on Native American populations. No one knows exactly what the mortality was. Conservative estimates are about 50%. It was probably closer to 90% or even higher. [narrator] Through trade between native peoples, diseases spread throughout the whole continent. Many natives die of foreign diseases without ever seeing a European. Microbes move faster than the conquistadors who brought them. Some 50 years after Columbus discovered the Americas, conquistadors and explorers find neither towns nor people. No one stands in their way. Most of the people are dead. And nature reclaims the land. Everything that they now find is pure wilderness, a Garden of Eden, without humans. [animals screeching] "A thousand different kinds of birds and beasts of the forest, which have never been known, neither in shape nor name, and whereof there is no mention made, neither among the Latins nor Greeks, nor any other nations of the world," reports a Spanish missionary. [honking] "It may be God hath made a new creation of beast." Explorers send exotic plants and animals, evidence of God's second creation, on the ships back to Spain. [parrot whistles] [speaking Spanish] Corn, chilli and pumpkins, domesticated in the New World, unknown in Europe. Tomatoes and potatoes. But there is an unwelcome passenger on board. An unintentional gift from the natives. It will lead to death in Europe. It will spread in the brothels in the ports and cities of the Old World. It will be painful. It drives its victims mad. And it can take a long, long time to kill. This is the French pox, or the Spanish sickness: syphilis. [thunder crashing] Europeans believe that syphilis is a punishment for their sins. They have no idea it comes from America, where more and more of them are desperate to go. And in the 17th century, a new wave of people head to the New World: the settlers. England has defeated Spain to become the new European superpower. The English crown sets out to claim its share. In 1607, the British found a colony on the east coast of North America, in what is now Virginia. They name it Jamestown, after their king. This will become their New World. Their job is to make money for the British trading companies that sent them here. The land they seize seems to be the perfect place to exploit. Forests and rivers, coasts and lakes, owned by no one. But not all Native Americans have succumbed to European diseases. And this land is neither empty nor uninhabited. It is the land of the Powhatan. Fifteen thousand people living in small communities. Around 200 villages on the coast and along rivers, in large houses surrounded by cleared forests and mixed fields of squash, beans and corn. These are farmers and hunters. There is no gold, no silver that settlers dream of. Just the land and its people. [speaking Algonquian] [giggling] [speaking Algonquian] [giggling] [narrator] For a while, the settlers and the natives lead separate lives. [twig snaps] This land is rich with resources that Europe lacks. In the long run, resources that are far more valuable than gold and silver. And there's more than enough for everyone. Europeans wanted to travel west, to the great empires of Asia. Instead the New World they found amazed them with its natural abundance. The first settlers in North America left Europe. They sailed from estuaries that were brown and muddy with sediment washed off the land. They were polluted with refuse, and so this was what they had grown up with, they were familiar with it. When they discovered the New World, they sailed into estuaries that were crystal-clear water. You could see all the way down to the bottom. You could see the vegetation on the bottom of the estuary. You could see fish in abundance, and they discovered almost miraculous, unbelievable quantities of fish in these estuaries and rivers. One particular kind of fish which very much impressed settlers was the river herring, or alewife as it's otherwise called. And seasonally these would ascend the rivers to spawn from the sea in their millions. For example, in the Potomac River near Washington, DC, during the 18th century, something like 750 million alewife were caught just from that one river in one year. It was a remarkable abundance and people described the rivers as having more fish than water. [narrator] Whole shoals are caught in the settlers' nets. In the 17th century, hundreds of thousands of tons of cod are shipped every year from North America to England, France, Portugal, and Spain. Fishing boats sink under the weight of their catches and the colonies thrive. It takes settlers only 200 years to achieve what had taken a thousand years in Europe: overfishing. Overfishing can impact on populations in many ways, and one thing that it does over a period of generations is to change the way that an animal reproduces and how fast it grows. So fishing tends to remove the biggest, oldest individuals from a population and by doing this, it changes the selective pressures on the population so that fish begin to grow more slowly. They reach reproductive maturity at a smaller size and earlier in life, and these things all reduce the productivity of a population. So over time, fisheries become less good at supplying the protein that we like them to do. [narrator] Fish are salted, packed and sent home for money. Along with them, the settlers send another resource that the Old World is desperate for. [man as settler] There are trees as far as the eye can see, such that a squirrel starting off at the Atlantic coast need never touch the ground till he got to the Mississippi. [narrator] This is so different from the Europe they left behind. They have finally found a replacement for something that is disappearing at home. An infinite, accessible source of the raw material of the age. The forests must fall if the settlers are to succeed. From now on the trees are doomed. [Radkau speaking German] [interpreter] When the first settlers arrived in the New World, they found forests of a kind they had never seen in Europe, endless forests with huge trees. Penetrating into the heart of the land became a war against the forest. The axe was the Yankee emblem. At the same time, forests were the great resource the land had to offer. You could make plenty of money exporting timber. In Europe, wood had become expensive. And so the greatest forest destruction in history now took place. [narrator] "The clearing of forests that seem to belong to no one and cost nothing goes so far that today many areas along the east coast and many of the Atlantic islands are completely bald. [man as settler] An incredible amount of wood is really squandered in this country for fuel. [narrator] Day and night, all winter, for nearly half a year in all rooms, a fire is kept going," said one European visitor. "The resources in this vast continent seem to be inexhaustible." But in time, fish stocks will dwindle in the Americas, too. Europeans change America by cutting down the forests and depleting the seas. They create this New World in the image of the one they left. But they haven't just taken away. They change this continent even more by what they bring with them. They leave their homes in search of their own land, something most could never dream of in Europe at that time. They come in search of religious freedom, in search of a better life. They believe they are responsible for their own success and happiness. For the first time, women settlers come too, and they bring a whole way of life with them. They bring animals and plants that are all new to the American continent. [sheep bleating] [squawking] Livestock and grains from Europe will transform the New World and make of it a true New England. With the newly imported plough, they will leave not one piece of land untilled. [horse whinnies] Domesticated livestock and metal tools, never seen on this continent. An environmental revolution takes place. In no time, their European wheat is growing in this foreign soil. Wheat, barley, oats and rye are brought to America. But in the process, some less welcome guests hitch a ride. [Isenberg] Europeans introduced crops such as wheat to the Americas, but in the bags of seed that they brought with them to the Americas, they also brought along seeds for weeds: dandelions, other kinds of weeds, and these are everywhere in the Americas now. [narrator] From the most insignificant weed to the continent's greatest mammal, nothing is untouched. America's native flora and fauna will be displaced. Where the bison once reigned, cattle will soon take over. To the settlers' delight, their livestock multiplies more quickly here than it did in Europe. In a few hundred years, European cows eat away the American grass and trample the soil, depositing their excrement and distributing the seeds of the weeds. [horses whinnying] The invasion of European animals changes the American landscape forever. Horses, pigs, sheep, goats, chickens, and huge herds of cattle take over North and South America. The cattle alone double in numbers every 15 months... and feed the settlers. The settlers defend themselves inside sturdy forts. But there are no shortages of any kind. Meat has become the cheapest food in the Americas. They are the best-fed people in the world. Very interesting knives. You have something a little better? [woman] We have this. Boys, you're gonna want a shot of rum. This is fresh rum from... [narrator] Hides are in great demand, in America as well as in Europe. And the fur of the wild animals they shoot brings in a steady export income. Some, like the beaver, are hunted almost to extinction. Settlers are not forced to adapt to the landscape. They domesticate and dominate it. "All trees were cut down and turned into pasture and gardens where all kinds of vegetables and root crops that we know in England grow in profusion." They replace the trees they cut down with their own trees. The Europeans bring peaches, pears, and plums. They bring figs, olives and bananas. Their trees will flourish. They never know how lucky they are. Because the settlers brought bees with them, for their honey. The native American bee pollinates only a few species, but European honeybees can live almost everywhere and will pollinate any plant in sight. Gardens will turn into plantations, for consumption at home and abroad. Apples will one day be a major industry in North America. With a yearly harvest of five million metric tons, it will lead worldwide exports, all beginning with European seedlings. This is biological imperialism in full swing. Europe's fruits and vegetables have conquered the New World. But it is also an exchange. It is the Columbian Exchange. European kitchens may not see native meat from America, bison or llama. But New World vegetables will make a big impact. The plant with the greatest impact on Europe needs a couple of centuries to take root in its culture. "This tuber is insipid and mealy. It cannot be classed among the agreeable foodstuffs. But it furnishes abundant and rather wholesome nutrition to men who are content to be nourished. It is justly regarded as flatulent, but what are winds to the vigorous organs of peasants and labourers?" wrote Diderot in his Encyclopaedia in the 18th century. First introduced into Spain, potatoes slowly spread to Italy and to northern and eastern Europe. By 1600, the potato has conquered Austria, Holland, France, Switzerland, England, and Germany. Frederick the Great himself urges its cultivation in Prussia. But it is the Irish who adopt the potato with open arms. They have a limited food supply and grain grown here has often been destroyed or burnt as the result of war. But the potato, safely underground, survives these hardships. In a hundred years, the Irish population more than doubles. And towns like Berlin grow into great cities. By 1700, there is an unprecedented population explosion in Europe... thanks to a plant from the faraway Andes. Yet only one animal from the New World sets foot in Europe. [turkey gobbling] The turkey. Domesticated by the Aztecs in Mexico, it enriches the European diet. [Isenberg] So, why was the Columbian Exchange so one-sided? Why did it go primarily in one direction, from Europe to America, with the exception of things like potatoes and potato blight? Why was Europe not overtaken by American plants and animals? It's difficult to say why something did not happen, but you have to remember that the ecological invasion was a cooperative enterprise, disease and plants and animals working together, and Europe remained densely populated. It didn't have diseases depopulate its people. And so you didn't have niches open up for livestock to graze, and then weeds to take over the areas that livestock had overgrazed and trampled. So without that critical part, it worked in one direction primarily. [narrator] The European elite want more than just potatoes from the New World. They want luxury products. Sugar and tobacco meet the requirements of the upper class. The first British settlers quickly acquire a taste for American tobacco and export large shipments to Europe. To satisfy such high demand, settlers build immense plantations. Growing sugar becomes a business on the same scale as tobacco. The new monocultures cover entire landscapes. For this sole purpose, some ten million Africans are transported to America, enslaved to cultivate luxury items for Americans and Europeans. [Isenberg] Because of the rapid depopulation of the Americas owing to disease, Europeans faced a shortage of labour in their effort to exploit the resources in the New World, particularly to exploit the soil. So the Europeans, first the Portuguese and then the Dutch, and then eventually the English, imported slaves from West Africa to cultivate sugar in the Caribbean and Brazil, tobacco in Virginia, rice in South Carolina, and by the 19th century in mainland North America, cotton. It's no exaggeration to say that these cash commodities produced by slave labour were essential to the export economies of the Americas. [narrator] By the 18th century, the metamorphosis of much of America is almost complete. New Spain and New England are fully established. Nature has been transformed and is in the hands of man. Now pioneers are heading west. There is still empty land in that direction. They will complete what was begun in the East. In the creation of the New World, perhaps 90% of the Native American people died. The people who took their place came from all over Europe, as conquistadors... settlers... colonists... and pioneers. And they came from Africa as slaves. But it was the transfer of animals and plants from Europe to the Americas that really made the creation of the New World possible. In today's chrome and steel cities, we sometimes seem so cut off from nature that it may be difficult to believe the Columbian Exchange ever happened. [car horn honks] But in the final analysis, the skyscrapers and the melting pot of the races owe their existence not only to humans, but also to the natural world. [Isenberg] People came to the Americas for many reasons. Some came to make money, some came for religious freedom, some came involuntarily as slaves, but those populations took hold in the Americas because of the accident of ecology. Because of the microbes, the plants, the animals that they brought with them that gave them an advantage over the people who were already here. And the legacy of the Columbian Exchange is also still largely biological, and that legacy will continue into the future. [narrator] It all began 500 years ago. Columbus had a vision. And three ships set out in a quest for India... and found the New World.