The Indus Valley civilization

At the same time as the Egyptians were raising pyramids and the Sumerians were inventing cuneiform, a third great civilization was thriving far to the east. The Indus Valley civilization grew up along the Indus River in what is today Pakistan and north-western India. It flourished from roughly 2600 BCE to 1900 BCE and was, at its peak, the largest of all the ancient civilizations by area — covering more than a million square kilometers.

Geography — The Indus River

The Indus River begins in the high Tibetan plateau and flows through the Himalayas south-west into the Arabian Sea. Like the Nile, it brought rich silt that fertilized the surrounding plains every year. The Indus Valley people farmed wheat, barley, cotton (one of the earliest places in the world to grow it), and raised cattle, sheep, and water buffalo.

Two Famous Cities — Harappa and Mohenjo-Daro

The two most famous Indus cities are Harappa and Mohenjo-Daro. Both were rediscovered by archaeologists in the 1920s, almost 4,000 years after they had been abandoned. Each city housed tens of thousands of people and was built to a careful plan. Streets ran in a perfect grid pattern, north-south and east-west, dividing the city into neat blocks. Most homes were built of standard-sized baked mud-bricks — the same size in every city across the civilization.

Brilliant Urban Planning

The Indus Valley people were extraordinary city planners — in many ways more advanced than other ancient civilizations. Every city had a sophisticated drainage system: covered brick sewers ran beneath every street, carrying waste away from homes. Almost every house had its own private bathroom with a brick toilet and a small bath. Large public baths, like the Great Bath of Mohenjo-Daro, were probably used for ritual cleansing. Storehouses for grain stood at the center of each city, and the standardized weights and measures used for trade were the same across hundreds of kilometers.

A Mysterious Writing System

The Indus Valley people did have a writing system — thousands of small seals have been found with symbols carved into them. But despite a century of effort, no one has yet been able to read the Indus script. We do not know what language they spoke, what they called themselves, or what their religion was. This mystery makes the Indus civilization fascinating even today.

A Quiet Decline

Around 1900 BCE the Indus Valley cities were gradually abandoned. Historians are not certain why. Climate change may have dried up rivers and ruined harvests. The Indus River itself may have shifted course. Trade with Mesopotamia broke down around the same time. Whatever the cause, the Indus people left behind some of the most peaceful and best-planned ancient cities ever built — and a culture whose influence is still being studied.