"So much about the ancient Indus River Valley remains a mystery."

When ancient people began to farm and live in cities, their existence became vastly more complex. But not all societies developed complexity in the same way. For example, consider the ancient Indus River Valley—an area around the Indus River, which flows through the present-day countries of Pakistan and India. People living there developed agriculture and cities not long after people in Mesopotamia. Like people in other cities, the people of the Indus River Valley farmed, traded long distances, and developed writing. But because of some of the choices they made, their society was unique in the ancient world.

With running water, private toilets, and sewers, these societies had the best sanitation system in the ancient world. Unlike other societies of that time, they didn’t have temples, priests, or a ruling class. We think they might have been a totally peaceful society, with few weapons or soldiers. But we still don’t know how to read their writing. That’s why so much about them remains a mystery.

Geography and environment

Located in a fertile floodplain, the Indus River delivered soil rich in nutrients to the people living along its shores. Once people learned to farm, this soil allowed them to grow many crops, some locally developed and others, such as barley, were adopted from Mesopotamia. The river also provided lots of water for those crops, and helped people move themselves and the goods they made on boats.

Beyond this floodplain rose hills and then great mountains—the Himalayas and Hindu Kush ranges. These mountains are among the tallest in the world, and they protected the people of the Indus River Valley from invasion. The mountains also contained resources like copper and lapis lazuli. To the west, however, the mountains were much smaller, allowing trade with Persia and Mesopotamia.

Along the banks of the Indus River, people developed technologies like pottery and copper tools. They were also careful urban planners. Early sites like Kot Diji and Amri (c. 5500–3300 BCE) were smaller, disorganized towns. But cities that formed later, such as Harappa and Mohenjo-Daro, were very carefully planned to take advantage of their environment. Some had walls, and many were organized with straight streets and carefully managed building styles. They also had among the world’s first sewer systems, which took human waste away from the cities.

The river was also a danger, though, because it sometimes flooded and, over time, changed its course. When the river flooded or moved, it would threaten whole communities. That may be what caused the Indus River societies to collapse.

Political structure

The major cities of Harappa and Mohenjo-Daro were home to thousands of people. The people there used a system of weights and measures, and carefully managed their resources. For example, to accomplish large building projects and to bring irrigation water to crops and sewers, large numbers of people would be organized to work together.

But here’s something surprising: Despite all this evidence of a highly organized society, there is no evidence that Indus River cities had individual rulers, powerful priests, or armies, and this is even more surprising because we have evidence that other societies during roughly the same period—including Mesopotamia and Egypt—were organized through kings and priests. Mohenjo-Daro, Harappa, and other Indus River Valley societies didn’t have big tombs or palaces. And although a few weapons have been found and some towns did have walls, there’s no evidence that they had armies.

"How do we know that these people did not have rulers, palaces, and war?"

We don’t really know how these cities were governed. Our best guess is that society was run by several wealthy families rather than a central ruler. We think this because we do have evidence that some people in these cities had more wealth than others. It seems like this group of important families shared power. Their biggest priority was probably managing farming, trade, and production of goods. That included trade with other local cities as well as with distant locations such as Mesopotamia.

The collapse of the Indus River Valley societies, around 1300 BCE, probably wasn’t caused by war or political unrest. The most likely cause was the shifting of the Indus River, which drowned many of the cities along its banks.

Culture

Indus River Valley cities left behind evidence of a rich, artistic culture. Unfortunately, we have a problem. We can’t read any of the writing!

Indus script writing has been found on several kinds of items, particularly on something called a seal. These seals have different images on them. Some images show up more than others. More than 65% of the seals found show a unicorn. Others have real animals. We think they represent a wealthy family or person. These might have been used to mark goods for trade. It’s possible that some of the seals were used in religion. For example, the seated male figure to the right, shown with a horned headdress, appears often. He may be a god, but we don’t know for sure.

The presence of animals on so many items may suggest that the people of cities like Mohenjo-Daro and Harappa believed that wild animals had spiritual importance. There are also clues that suggest other religious practices. For example, a very large bath at Mohenjo-Daro may have been used for ritual bathing, which people would do to purify themselves. But there are no large temples and people were buried with few goods or ceremony.

As for everyday life, we know that the inhabitants of the Indus River Valley wore cotton cloth, and we have some figurines that show them with robe-like clothes and elaborate hairstyles. Because we have also recovered some dice, board games, and musical instruments, we have some evidence that they entertained themselves with games and music.

Society

While Indus River Valley cities don’t show evidence of palaces and kings, they do show some social stratification based on economic status. For example, houses toward the centers of cities are generally larger than those at the edge. It’s also clear that the cities were organized to provide some public spaces like markets as well as private homes.

Families may have specialized in producing or trading certain goods. Different families may have managed pottery, metalwork, and trade with other cities. Still, the many large baths and wells suggest that people were used to sharing resources and working together.

We don’t know as much as we would like to about these ancient cities, but we’re learning more every year. For example, archaeologists in India have uncovered an ancient city beneath the modern city of Haryana. Like other Indus River Valley sites, it shows a well-planned city with wide roads, drainage, and a shared granary for storing food. It also has lots of artifacts, such as terracotta statues, weights, bronze items, and jewelry made from gold and semiprecious stones. A granary made of mud bricks with many chambers inside was discovered, suggesting advanced food-storage techniques. An ancient port city has also been uncovered at another site in Gujarat, India, which shows that these communities traveled the ocean on ships.

In the future, we may know a lot more about these ancient city-builders, but there are still many mysteries left to solve.