A Journey Across the Map and Through Time
1Our journey starts at Mohenjo-daro in about 2500 BCE. It was one of the largest cities of the Indus Valley civilization, which flourished from about 2600 to 1900 BCE. Its streets were laid out in a grid. Houses were built of baked bricks made in the same proportions, and many had a bathing room whose waste water ran into covered drains under the streets. Near the center stood the Great Bath, a large brick pool. Historians think it may have been used for religious washing, but they are not sure.
2Upriver at Harappa, archaeologists found a similar street plan and bricks of the same proportions. Merchants in many Indus towns used stone weights that came in the same set of sizes. Craftworkers carved small stone seals showing animals and a short line of symbols. No one has yet learned to read this Indus script. At Lothal, near the coast, archaeologists uncovered a long brick basin that many of them think was a dock, and Indus seals have turned up in Mesopotamia. By about 1900 BCE the large cities had emptied. Historians debate why; ideas include rivers changing course, a drier climate and a drop in trade.
3Now the journey jumps ahead about 1,600 years. In about 321 BCE, Chandragupta Maurya took power and built the Maurya Empire, the first to unite most of the Indian subcontinent under one ruler. A great road ran from Taxila, a center of learning, east across the plains to the capital, Pataliputra.
4A Greek ambassador named Megasthenes lived at Pataliputra and wrote a book describing a huge city surrounded by a wooden wall. His book is lost; we know parts of it only because later Greek and Roman writers quoted it. Chandragupta's grandson Ashoka conquered Kalinga, on the east coast, in about 261 BCE. In his own words, the war killed and uprooted many thousands of people and filled him with regret. Afterward Ashoka followed Buddhist teachings and had messages carved on rocks and stone pillars across his empire. They asked people to avoid violence, be kind to animals and respect every religious group. He also wrote that he had wells dug and shade trees planted along the roads.
5The journey ends in Pataliputra centuries later, when it was again a capital, this time of the Gupta Empire (about 320 to 550 CE). In 499 CE the scholar Aryabhata, who is believed to have worked near the city, wrote that Earth spins on its axis and gave pi as about 3.1416. Indian mathematicians also used a place-value system with nine digits and, later, a symbol for zero. Arab scholars carried these numerals west, and they grew into the digits used around the world today.