-Throughout the ages, there have been great empires and civilizations that have risen up, their creators ruling nations, regions, and continents for hundreds, even thousands of years.

Some of the great legacies and accomplishments of these empires may be lost in the mists of time, but from what they have left behind in rock and ruin, we can trace remarkable stories.

♪♪ -Throughout its history, Mexico has been convulsed by a series of epic, violent, and bloody struggles that have defined the culture and identity of this complex nation.

-I think it was Edward Gibbon who said that history is mostly a record of the crimes, follies, and misfortunes of mankind, which is a bit of a downbeat view.

But Mexican history has a lot of that.

-When Spanish conquistador Hernán Cortés met Aztec Chief Montezuma, they created a new nationality in the instant they met.

But in the following centuries, divisions ran deep and continue to this day between the indigenous and European peoples and between church and state.

After 300 years of Spanish occupation, Mexico would, in the 19th century suffer five foreign invasions in less than 100 years from Spain and two each from France and the United States.

These influences have created a unique culture and nation that still struggles to break free from a troubled past.

♪♪ ♪♪ Mexico was home to ancient civilizations hundreds of years before the Christian era.

At Teotihuacan, just outside Mexico City, a city of wide avenues and palaces emerged around the time of Christ.

It grew into a city of more than 100,000, centered around two giant pyramids of the sun and moon.

It prospered for nearly a millennium and its belief system lived on and was treasured by the Aztecs for centuries.

♪♪ In Jalisco, not far from Guadalajara, these unique circular pyramids were constructed approximately 2,000 years ago by the Teuchitlán culture that had thrived in the Tequila Valley region between 300 BC and 980.

This culture is notable for its use of conical step pyramids.

Apart from one smaller pyramid in Mexico City, these are the only round pyramids in the world.

On the Yucatan Peninsula and beyond, the Maya erected dramatic temples from 700 AD in Chichén Itzá, Tulum, and Coba.

The Maya developed a writing system and complex ideas in the fields of astronomy and mathematics.

In 1517, the first Spaniards arrived in what is today known as Mexico and skirmished with the indigenous tribes of one of the many descendants of Maya off the Yucatan coast.

In fact, the Spaniards were searching for a route to Asia, and they thought they'd found it.

-They were there for God, glory, and gold.

They wanted to spread the faith -- some of them, not all of them -- glory for themselves -- prestige and authority -- and gold.

These two big chunks of humanity that had been separated for millennia -- those who lived in the Americas and those who lived in Eurasia -- suddenly come together, and they didn't know each other existed.

And suddenly, here in Mexico and in Peru, there's this collision of two groups, two cultures who had no idea the others -- where they came from or what they did or how they existed.

So it's a remarkable moment in human history.

-For a few decades, they didn't even realize that America was a new thing.

They thought they were in Asia.

Columbus died convinced that he had reached some part of Asia.

-The Spaniards were also possessed with the crusading Christian spirit.

-Columbus himself told Isabel and Fernando, the king and queen of Spain at the time, that the whole experiment was for the conquest of Jerusalem.

The mentality in the early years was completely rooted in the legacy of the medieval period.

There's nothing really forward-looking about it at all.

-Another Spanish expedition under Hernán Cortés landed near Cozumel in February 1519.

♪♪ The Indians were happy to tell Cortés about gold and the riches of the Aztec Empire in central Mexico.

♪♪ Two months later, on Easter Good Friday, Cortés landed on the Veracruz coast, site of the modern day city.

He named it Villa Rica de la Vera Cruz.

In English, "Rich Town of the True Cross."

♪♪ He then relocated up the coast to Antigua, a sleepy town today, but on a river.

The ruins of a customs post are still here, overtaken by the roots of giant trees.

America's first church was erected here in 1521.

♪♪ It was near here that Cortés would have his first encounter with the ancient Mesoamerican civilization.

The mysterious Olmecs, Mesoamerica's earliest known civilization, built their first great center in Veracruz State around 1,200 BC.

Skilled stone artisans, they created giant sculptures -- grim-faced helmeted heads up to three meters tall and weighing 20 tons.

Classic Veracruz civilization was at its peak here 1,500 years later in centers such as El Tajín.

♪♪ ♪♪ El Tajín had already fallen into ruin by the time Hernán Cortés arrived in 1519.

♪♪ It was here, at nearby Zempoala, that Cortés first encountered the ancient Mesoamerican civilization.

They were the Totonacs.

Among the ruins of Zempoala today is this sacrificial altar where captured prisoners would be forced to fight their captors to the death, sometimes while having their ankles tied.

♪♪ Cortés befriended the Totonacs, who became his allies against the Aztecs, who had, by this time, subjugated them.

He then navigated ancient Indian routes through the Sierras, which separated the coastal lowlands of Veracruz and the higher altitude plateaus of the Mexican heartland.

Cortés arrived in modern Mexico City when the Aztec empire was at the height of its wealth and power.

Montezuma II ruled over the Central and Southern Highlands and extracted tribute from lowland peoples such as the Totonacs.

Cortés destroyed the empire of the Aztecs with a force of just 600 men and 16 horses, taking its capital city, Tenochtitlán, after a bloody four-month siege.

-The conquistadors, when they first saw it, were utterly amazed.

They compared it to Venice because of its system of canals.

♪♪ At that time, Tenochtitlán was one of the most populous cities on Earth, and certainly it was more populous than any of the cities that the conquistadors themselves would have seen up until that point.

-Tenochtitlán covered some 14 square kilometers and was connected to the surrounding countryside by three causeways.

The city itself was laid out in a grid pattern, with many canals permeating through the city.

At the heart of the city was a large sacred precinct dominated by the huge pyramid known as the Templo Mayor.

On top of the 60-meter-high pyramid platform reached by two flights of steps, were two twin temples.

The north side shrine was dedicated to Tlaloc, the god of rain, and the other, on the south side, was dedicated to Huitzilopochtli, the god of war.

The Temple of Tlaloc marked the summer solstice, symbolic of the wet season, whilst Huitzilopochtli marked the winter solstice, symbolic of the dry season and a time for warfare.

The monumental steps leading to Tlaloc's temple were painted blue and white, the former color representing water, the element so strongly associated with the god.

In contrast, the steps leading to Huitzilopochtli's temple were painted bright red to symbol blood and war.

Sacrifices, including human ones, were carried out at both temples to feed and honor the gods.

A typical sacrifice involved the victim having their heart ripped out, being skinned, decapitated, and then dismembered.

Following all that, the corpse was flung down the steps of the pyramid to land at the base.

-Cortés kidnaps Montezuma.

He keeps him under armed guard and tries to use him as a puppet ruler to control what was an empire of millions of subjects.

He was assisted in his conquest of the Mexica or Aztec Empire by a very, very large number of indigenous allies.

Hernán Cortés' strategy was very much a divide and rule strategy.

By allying himself with the enemies of the Mexica, he was able to call then upon tens of thousands of indigenous allies to help him and assist him when it came to armed confrontations with the armies of Montezuma.

The death of Montezuma, following his kidnapping and captivity by Cortés' men, left the Mexica Empire headless.

-Montezuma, terrified by the Spaniards' military tactics and technology, was convinced that Cortés was the god Quetzalcoatl making his long-awaited return.

When the Aztec capital fell in 1521, all central Mexico lay at the conqueror's feet.

The Spanish King Charles V hastened to legitimize Cortés' victorious pirate expedition and ordered the forced conversion to Christianity of the new colony to be called New Spain.

On top of the Aztec temple, Cortés constructed a church, still here today and still the largest in Latin America.

Cortés set about creating a new city upon the ruins of the Aztec capital, collecting tributes, some of them in labor, that the Indians once paid to Montezuma.

Throughout the following centuries, Spaniards remodeled the conquered city, reorganized its governments, and converted the devastated population to Christianity.

-The way in which Christianity spread in Europe is very, very similar, isn't it?

It wasn't a total replacement of one kind of universal view of the world for what was there before.

It was a very gradual incorporation of different things.

And most of the festivals that Christendom celebrated had pre-Christian roots.

The situation in Mexico was exactly the same, exactly the same as England under Augustine or Germany under Boniface, the famous Boniface of Crediton, who was responsible for the evangelization of Germany.

So they were very much thinking along those lines.

They were doing the same thing as Christian missionaries did in Europe in late antiquity and the early Middle Ages.

-Though it took decades and sometimes longer for the Spanish to subjugate some parts of the country, such as Oaxaca, a Franciscan friar writing 10 years after the conquest observed, "More than 250,000 men have been baptized, 500 temples have been destroyed, and more than 26,000 figures of demons, which the Indians worshiped, have been demolished and burned."

-You can't really understand modern Mexican culture without the the legacy of these remarkable friars that Christianized people in the 16th century, because they did it in a way that is very medieval.

You know, it's not -- They arrived before the Reformation.

So they spread Christianity as something that was not necessarily opposed to anything.

You know, it was a kind of natural thing that these people would naturally learn through the use of reason.

And the example that they gave them in liturgical rituals and all that sort of thing, that it would be a gradual process.

♪♪ -In the decades after the conquest, Veracruz was established as the main gateway between Mexico and the outside world and would remain so for 400 years.

Invaders, settlers, priests, incoming and outgoing rulers, new settlers, silver, and slaves all came and went from here first.

Over time, their first sighting would have been this place, the fort of San Juan de Ulúa, a stone encrusted coal and brick edifice that has survived for more than 500 years.

The fort's strategic position on an isthmus enabled it to protect the port and fight off potential invaders and pirates.

It was said that whoever controlled the fort also controlled Mexico.

Juan Ortiz of Veracruz University has studied the fort and its history.

-[ Speaking Spanish ] ♪♪ [ Bell tolling ] -The Spaniards would rebuild cities in the new world in the same manner as they did in the old, striving to create straight streets, square blocks, and rectangular piazzas.

♪♪ In these colonial heartlands near Mexico City, they created new cities like Morelia, one of the first new cities in New Spain.

It's elegant stone buildings still celebrate its Spanish past, as do its residents.

The Spaniards constructed giant aqueducts, bringing water to their new cities.

The cathedral here took more than 100 years to build.

The clergy were a dominant force in Spanish Mexico.

The seminary here for priests in the Palacio Clavijero, was home to a Jesuit school of Saint Francis Xavier.

It's now an art gallery.

♪♪ ♪♪ [ Bell rings ] One of the grandest of all Jesuit monasteries was this one here in Tepotzotlán, just outside Mexico City.

It was here that many Jesuit priests would set out on their journeys around the country to convert the native population.

The Iglesia de San Francisco Xavier here has one of the most spectacular facades in all Mexico.

Inside the vast monastery next door, novice priests would gather in a grand chapel facing this heavily decorated altar.

Were they in any doubt about the power of their faith?

♪♪ On the vaulted ceilings were the coat of arms of the Spanish Empire's religious zealots, the Jesuits, the Franciscans, Augustines, Benedictines, and Mercedarians.

The cloistered quarters gave way to a vast orchard which fed its occupants.

♪♪ ♪♪ The monastery today contains an extraordinary collection of religious and colonial art, which gives an insight into life in colonial New Spain.

♪♪ ♪♪ ♪♪ In the decades following the conquest, Spanish conquistadors and priests would set out and explore in all directions -- south, east, west, and north into the desert -- where they would aim to expand and build on the foundations of the new empire they had created.

-The reputation of the conquistadors has suffered a lot.

But we often forget the admirable endurance.

You know, if you just think in terms of human endurance, it was an enormous achievement and something that needs to be understood from the inside.

So, you know, try to get away a little bit from the prejudices that we have inherited from nationalist histories and from the legacy of what's known as the Black Legend, which was all the propaganda against Spain that started in the late 16th century, especially in Holland and England, who were very, very interested in painting a very dark image of Spain, you know, as if it was full of people who were just cruel barbarians.

The conquistadors were painted with that brush.

And it's a very difficult prejudice to get rid of.

But I think it's the role of the historians to try to get inside the mentality of these people.

That's what I've been trying to do.

Not finding it very easy, actually, because people just raise their eyebrows and think that I'm some kind of fascist, crypto fascist, because I want to understand these people who should not be understood.

They should just be condemned out of hand.

-A very important point that I think has to be stressed is that, in the first hundred years of the Spanish colonial system, the indigenous population was decimated by the impact of European diseases, but also brutal forms of exploitation and war.

And that is an aspect of the colonial system that led to a massive reduction in the indigenous population from the beginning to the end of the 16th century, which, to some extent, then required the Spanish legal system and colonial system to respond by reforming or changing the most exploitative aspects of the system that they had set up to preserve and help recover the remaining indigenous population, which did start recovering from the 17th century onwards.

-They kept the indigenous languages.

They were very good at using whatever they found that would not directly contradict the basic principles of Christianity, but there were very few things that would contradict them.

Things like, of course, the problem with polygamy and the problem with human sacrifice.

They got rid of human sacrifice almost immediately.

It's not as if it was a very popular practice.

The indigenous peoples carried on sacrificing, of course, because they had this idea that blood was very important to keep the deities alive.

And the idea that the deities would just disappear with the arrival of the Christian God was something that took a very long time to sink in.

So there was a lot of adaptation with with feasts and celebrations.

Exactly the sort of thing that happened in Europe with the cult of the saints and their relics and their miracles and their traditions and all that sort of thing.

It was very easy to incorporate all this to practices that were there, that existed there before in the native rituals.

Any religion that is going to be meaningful or effective has to have roots in the in the local cultures.

And this is what you see in all the survivals that are very, very often seen as the authentic Mexican thing that a lot of people try to trace back to pre-Hispanic times.

And a lot of people say that the Day of the Dead must be a pre-Hispanic thing, but it just happens to be on the 2nd of November, which is All Souls', which is a Christian festival for the Day of the Dead, that, you know, you have to... And in Mexico, it just happened to be -- to have all these visual aids that the indigenous societies used, you know, the skulls and bones and all this kind of thing was very much part of the pre-Hispanic indigenous cultures.

But it was incorporated into a Christian festival.

And it tells a very Christian story.

-So this is a very paternalistic idea that Indigenous people and communities needed to be protected from the less Christian aspects of Spanish culture that might influence them and also to protect them from forms of exploitation.

Most of the early colonists or conquistadors, as they're often referred to, participated in those expeditions in order to make themselves rich, make themselves powerful.

And you know, the system was open for abuses.

So the separation between -- that was envisaged for these two systems was about preserving the stabilizing aspects of indigenous societies while facilitating their conversion to Christianity.

-The discovery of silver in Zacatecas in the 1540s drew settlers there to exploit the mines.

Silver mining not only became the engine of the economy of New Spain and vastly enriched the mother country, but transformed the global economy.

These giant mines produced much of the world's silver for more than 250 years.

-Well, of course, the search for gold was paramount because, from the very beginning, that was the contracts that conquistadors, explorers signed with the monarchs would give the monarchs a part of whatever they found.

And as you know, in the 16th century, all European monarchs were cash strapped.

They were desperate for money, especially gold.

So it was very attractive.

You know, one of Columbus' selling points was that he would find gold.

They needed to find gold in order to prop up the bankrupt Spanish monarchy.

♪♪ -Silver became really the heart and soul of colonial and 19th century Mexico.

There were metals that were used by the indigenous peoples before the Spanish arrived, but there wasn't systematic exploitation of them.

By the 1540s and 1550s, when they were getting these mines operated, the immense amount of wealth that they produced was, for that time, incalculable.

♪♪ -Guanajuato was the jewel enveloped by mountains that have given up their precious seams of silver.

The mines here in Guanajuato produced a quarter of the world's silver, extracted from giant sites, some of which are still active.

The ruins of mines can be seen on the hills that surround this city.

Professor Javier Garciadiego is one of Mexico's leading historians.

-[ Speaking Spanish ] -Western Europe, particularly, was suffering from a shortage of exchange medium, and they were in very, very great need of gold and silver, especially because they they were experiencing an imbalance of trade with the East.

Mexico becomes the world's largest producer of silver by the 18th century and therefore, fulfills a major role in the international economy.

♪♪ -Querétaro was one of the so-called silver cities that sprung up on the back of this trade.

Grand churches and monasteries were built and an aqueduct which snakes through a now modern city.

♪♪ Sao Miguel Allende, which would take its name from a Mexican independence hero in the 19th century, is now a celebrated destination for cultural tourists from the United States and Europe.

♪♪ From these silver cities, the Spanish created a network of so-called royal roads to the outlying areas of the territory of New Spain, particularly the North.

Expeditions and caravans would travel these roads all the way to Northern California and Santa Fe in New Mexico, establishing fortresses, missions, and settlements along the way.

These caravans were sometimes three miles long, and the road journeys to missions at the edge of empire could take two years.

-The network of Royal Roads were perhaps one of the most vital aspects of colonization for the Spaniards.

Think how important the imperial roads were to the Romans.

Silver and especially gold was the reason why they were there.

Obviously, it was very important to them to find ways to keep the Spaniards, the conquistadores, in the New World, because after they had taken as much as they could out of tribute, after they'd sacked the cities and taken as much gold and silver as they possibly could -- especially gold.

They were not so interested in silver at the time -- why would they stay?

♪♪ -Beyond the colonial heartland, there were mountains and deserts.

The Royal Roads would stretch north for hundreds of miles into New Mexico.

♪♪ In these outlying lands, the Spanish built bridges in places like Olesco.

♪♪ And the routes were protected by forts like this one nearby.

♪♪ The Spanish also introduced systems of social control, including a complex caste system.

-Throughout the 300 years of colonial rule, if you were born in Mexico, or even if you were born abroad, you were designated a caste and that was registered in the parish records.

So the whole social system, in terms of where you were in it was effectively described by a hierarchical system of castes with African slaves or freed at the bottom, Indians the next up, so-called mestizos.

Further up, mestizo is somebody who is of indigenous and Spanish descent.

Then the Creoles, who were White Mexicans, Americans, born in America, in the Americas.

And at the top were the so-called European Spaniards, the Europeos.

And, so, that was the system.

And belonging to that particular caste confers certain rights, but also certain limitations, particularly the lower you went.

♪♪ ♪♪ -This incredible work of art, discovered at the Jesuit monastery in Tepotzotlán, illustrated 17 racial categories by which people were categorized under Spanish rule.

Mestizos had both Spanish and Indian parents.

Mulattoes had Spanish and Black parents.

And at the bottom, zambos, who had Black and Indian parents.

♪♪ Meanwhile, Spanish lords built huge feudal estates with Indian farmers as serfs.

This hacienda outside Guanajuato gives an insight into life for the hacienda owners.

The Spanish elite built lavish homes filled with ornate furniture and draped themselves in imported velvet satins and jewels.

Haciendas originated from the Spanish land grants made to many conquistadors and crown officials.

But many ordinary Spaniards could also petition for land grants from the crown.

♪♪ The system is thought to have started when the Spanish crown granted to Hernán Cortés the title Marquis of the Valley of Oaxaca in 1529.

Cortés' hacienda is still here today.

The booty of silver and gold made Spain the wealthiest country in Europe.

Over the three centuries of colonial rule, the Spanish crown appointed 361 viceroys to govern the jewel of its Latin American empire.

♪♪ The Spanish colonialists may have created an elaborate racial caste system classifying people by racial mixture, but this system would break down in the very late colonial period, and after independence, the legal notion of race would be eliminated.

-And yet it was retained really to enable the people at the very top to remain at the very top.

If everyone else was struggling to sort of leapfrog and to get higher in the system so as to be able to get more rights and more freedoms, that was great because they were basically competing with each other.

All caste distinctions were removed and everybody became an equal citizen of the Spanish realm, be it American or European.

So, overnight, equality was declared and caste designations were abandoned.

So the church had quickly to sort of fold up their old books and open new books.

And everybody went in according just to the day you were born, not according to which caste you belong to.

-A key aim of the colonization took on elements of a religious crusade.

Scholars of the Spanish conquest defend the invaders' relationship with the indigenous population and their forced conversion to Christianity.

-It is a very -- a much less rigorous, top down oppressive system than the one we are -- we've been taught to believe was in place.

-[ Speaking Spanish ] -The colonial period, once the conquest was over, was relatively peaceful.

There were some rebellions, but not very big ones.

Not until you get to the independence wars do you have really big wars again.

-But before that, Franciscan and Augustine friars converted millions of Indians to Christianity.

However, the northern area of Mexico, a region of nomadic and semi-nomadic indigenous populations, was not densely settled.

Spanish conquistadors, explorers, and priests had all explored these vast desert lands to the north.

Beyond this frontier, there were rich grasslands where indigenous Indian tribes tended their wild buffalo herds, millions strong.

But Spanish settlements would now endure hostile raids from Apache and Comanche warriors migrating south, under pressure from European settlers moving west in North America.

María Terrazas is a professor of history and has studied these nomadic Indian tribes.

-[ Speaking Spanish ] -Spain could never properly control its northern frontiers, building fortresses known as presidios in these isolated desert outposts.

A string of 18 presidios near Janos in the north defended the borderlands.

These were often built alongside missions.

This is Mission San Xavier del Bac, the oldest mission in the US, located south of Tucson in Arizona, just 50 miles from today's border with Mexico, founded by Jesuits who had also founded dozens of others in the Sonoran Desert.

The Jesuits built this mission at Tumacácori at the end of the 17th century.

Their leader, Father Kino, rode into the Santa Rita Valley and befriended the local Indian tribe.

The plan was to turn these outposts into self-supporting Christian communities defended by Spanish troops.

The settlements fought off Apache raids for centuries.

-[ Speaking Spanish ] ♪♪ -It was from here that the Spanish explorer de Anza stopped and rested on his historic expedition of discovery.

He would follow the rivers and water, but would also set out across the desert to eventually reach California, a journey that would take two years and cover 2,000 miles.

♪♪ En route, he crossed the Colorado River here at Yuma.

The Indians here, called the Yuma, who controlled access to the Colorado, would later shut down this crossing for decades, forcing expeditions to California to travel by sea up the Pacific coast, a journey that would take two months.

The Yuma Revolt turned California into an island and Arizona into a cul de sac, severing land connections before they could be firmly established.

Indian wars in these borderlands would last for more than 300 years.

The Comanche and Apache would prove a hostile foe for Mexicans and then Americans until the end of the 19th century.

-[ Speaking Spanish ] -As in the Sonoran Desert, the Spanish built a chain of missions further north.

From 1769, they constructed 21 missions in present day California along its own Royal Road, the El Camino Real.

These missions were also built in an effort to exclude growing British and Russian claims to the territory.

The frontiers were defended fiercely, but ultimately unsuccessfully by the Spanish and soon to be Mexican armies and their mercenaries, including a sizable number from Ireland inspired to join their Catholic brothers in both defending and promoting the faith.

-There were connections between Ireland and a kind of governing sense on Spain and a governing sense because of their shared Catholicism.

But I think it extended beyond that, as well, in terms of how the trading network of the Spanish empire operated, and also the Irish mercenaries did acquire an international reputation for being skilled fighters.

And, so, when the Spanish were trying to shore up the boundaries of their empire in a territorial sense, so particularly at its peripheral edges in the north of Mexico and in different parts of South America, defending against encroachments from the British, the French, the Americans, and various indigenous communities, as well.

The Irish were often sought out as as strong military leaders to staff those garrisons.

♪♪ -Hundreds of miles south, other indigenous tribes from New Spain's ancient and Mesoamerican civilizations had long been subjugated.

Although the Spanish had developed elaborate systems to accommodate indigenous people into their empire, hundreds of sites such as the magnificent El Tajín in Veracruz State, which had been abandoned in the 12th century, 300 years before the Spanish arrived, still lay undiscovered.

El Tajín was only rediscovered in 1765, more than 500 years after it was abandoned.

The existence of this and many other sites buried in the jungles were only brought to light in the 19th century by discoveries of explorers such as the British artist/explorer Frederick Catherwood, who produced these magnificent artworks which captured the attention of the outside world.

♪♪ ♪♪ By the beginning of the 19th century, Spain's grip on both its northern borderlands and the heart of its Mexican empire was slipping, as it was throughout all of its colonies in Latin America.

In 1808, Napoleon invaded Spain, deposed its king, and crowned his brother, Joseph Bonaparte.

To many in New Spain, allegiance to France was unthinkable.

The next logical step was revolt.

Spain's tenuous hold would be exposed as Mexico hurtled towards independence.

The War of Independence would last more than 10 years.

Afterwards, an independent nation, Mexico, would chaotically emerge.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪