When we study ancient societies, we often think of them as separate “civilizations.” But in reality, every society on Earth is connected to others. These connections are one of the biggest causes of increasing complexity. As societies share more, innovations increase and complexity grows. In the Americas during this historical period, there was plenty of trade and interaction happening across vast distances, linking societies in every corner of the American continents and driving social and technological change.

We know about these trading systems because there’s lots of evidence of it. We’ve written reports about the extensive trade carried between islands and mainland in the Caribbean and up rivers like the Mississippi by small boats. We have tons of evidence of the immense road structure created by the Inca to span the mountains, valleys, and ravines of the Andes mountains. More and more, ground-penetrating radar and other technologies are helping archaeologists trace ancient trade routes in the Amazon rainforest and across the hills of Mesoamerica and the American Southwest. We’ve found minerals that somehow traveled thousands of miles across North America, and crops like maize and potatoes that spread from one place across entire continents.

Geography and environment

The trade networks that developed in the Americas were different from those that developed in Afro-Eurasia. The people who lived in the Americas before 1500 CE faced unique challenges in building their trading networks. These challenges shaped trade in these regions.

Here’s an example: One of the interesting features of trade in the Americas before 1500 CE is that there was no wheeled transport—no carts or chariots—to carry cargo long distances. The wheel was of huge importance to trade in large parts of Europe, Africa, and Asia. Why not here?

At one time, some scholars thought that the lack of wheeled transport in the Americas was a sign that societies there were not as advanced as those in Afro-Eurasia. But today we know this isn’t the case. In fact, there were lots of wheels in the Americas before 1500. We know this because archaeologists have found ancient toys in Mesoamerica that have wheels. But as far as we know, wheels weren’t used for transport. Why?

The main reason was lack of domesticated animals to pull wheeled vehicles. The Americas simply didn’t have any indigenous domesticable animals—like horses and oxen—that could pull carts. In fact, there were very few animals that could be trained carry a load at all. The only pack animals in the Americas were the llamas and alpacas that were domesticated in the Andes mountains of South America—and they weren’t physically suitable for pulling wheeled carts.

Another reason that wheeled transport wasn’t used was the geography of the Americas. Thick forests and big mountains made this sort of travel difficult. And then there was the fact that many societies in the Americas had developed sophisticated systems of runners and porters—people carried messages and loads long distances themselves.

Nonetheless, while there weren’t vehicles with wheels, caravans of camels, or large sailing ships, there was still a lot of trade going on in the Americas before 1500 CE.

In the middle of everything

When looking for evidence of long-distance trade networks in the Americas, the best place to start is Mesoamerica (today’s Mexico and Central America). It was the most urbanized region of the Americas and it was kind of in the middle of everything. In fact, that’s what meso means: middle.

Mesoamerica has few navigable rivers and its terrain isn’t suitable for wheeled vehicles. Most merchants had to carry goods themselves, on their backs. The archaeologist Kenneth Hirth claims that “Mesoamerica had the worst transportation system in the ancient world.” Despite this challenge, societies in Mesoamerica still developed active trading networks that moved goods long distances. We can study them by looking at two important Mesoamerican cities separated by 25 miles—and by 1,000 years: Teotihuacan and Tenochtitlán.

Teotihuacan

In the fifth and sixth centuries CE, Teotihuacan was one of the largest cities in the world, home to as many as 200,000 people. During the Classic Period of Mesoamerica (100–650 CE), it was the center of regional trade networks extending through Mesoamerica and beyond.

Teotihuacan was an important market center and trading power because its rulers controlled access to two of the largest sources of obsidian—a natural glass formed by the cooling of volcanic lava. Since metalworking was rare in Mesoamerica, obsidian was the best option for weapons and other sharp tools—if you could get it. Like Afro-Eurasian societies that had access to iron and copper, Mesoamerican societies that had reliable access to obsidian had a big advantage.

Merchants from Teotihuacan traveled across Mesoamerica and other regions, trading obsidian and bringing back luxury goods. Archaeological evidence suggests that Teotihuacan’s trade networks reached from today’s Southwestern US to Panama. However, its strongest trade was with the Maya city-states (in today’s Mexico and Guatemala). Teotihuacan and the Maya exchanged goods, ideas, and people in times of war and peace. Maya merchants traveled the coasts of Mesoamerica in huge canoes, carrying jade, cacao, honey, and feathers, among other luxury items.

Tenochtitlán

Just 25 miles south of Teotihuacan sits the capital of the Aztec Empire—Tenochtitlán. Well, it used to be Tenochtitlán. Today, it’s Mexico City, itself a center of global trade and home to almost 21 million people. But beneath the concrete of this modern city lie the ruins of Tenochtitlán. Almost 1,000 years after the collapse of Teotihuacan, the huge markets of the Aztec Empire dominated trade in Mesoamerica.

By the fifteenth century, the Aztec Empire controlled extensive trade routes across most of Mesoamerica. Their capital city, Tenochtitlán, sat on a lake. With its huge markets, straight streets, and monumental architecture, Tenochtitlán was home to over 200,000 people—larger than London, Paris, or Madrid at the time. The nearby market of Tlatelolco was visited by tens of thousands of people every day.

Trade was central to life in the Aztec Empire. The Aztec pantheon—the group of gods they worshipped—had a god of commerce, named Yacatecuhtli, who protected faithful merchants and travelers. Aztec merchants, who were called pochteca, traveled all over Mesoamerica, carrying their goods on their backs. They walked through the empire and beyond, buying and selling luxury goods like turquoise, quetzal feathers, cacao, obsidian, and jade.

The pochteca were their own separate social class and developed a complex hierarchy, from minor merchants who sold handmade goods at local markets to very wealthy individuals running large businesses that traded with other city-states. Like merchants in Europe and China, many pochteca hid their wealth to avoid angering the nobility, who were jealous of merchants from a lower social class who had more money than them.

Long-distance networks in the Americas

Chasqui: inca messengers who ran long distances to deliver messages and goods

While we’ve focused on Mesoamerica, there was lots of trade happening elsewhere in the Americas. In the Mississippi River Valley, trade networks stretched from Wisconsin to the Gulf of Mexico. Caribbean societies traded with communities in South America. The Puebloan peoples in today’s Southwestern US traded turquoise across a vast network stretching from California to Northern Mexico. Puebloan turquoise has been found in Aztec sites, and Aztec cacao and feathers have been found in the American Southwest. This is all evidence of long-distance trade. The two societies were separated by 1,200 miles—about the same distance as exists between Rome and Egypt.

And then there was the Inca road system. The Inca built thousands of miles of stone-paved roads and hanging bridges across the steep Andes mountains. These roads connected cities, farms, and military outposts, making it easier to move goods, people, and messages. Since they didn’t have carts, the Inca used trained runners called chasqui to carry messages, and llamas to carry supplies. This vast network of roads helped the empire stay organized and allowed the Inca to trade food, clothing, pottery, and tools across many different regions.

These systems of exchange were unique to the Americas, and they helped this region develop incredible complexity over the period before 1500 CE. The differences between trade in the Americas and trade in Afro-Eurasia reveals how societies develop in ways that reflect their unique environments and responses to opportunities and challenges, and that there’s more than one pathway to complexity.