Indus River Valley (Harapan or Indus Valley) Radiocarbon dating indicates that it arose about 2500 BCE in the greater Indus River valley of Pakistan and northwest India. The two major cities of the culture were Harappa and Mohenjo-dara. 1. Large Rivers and Irrigation Techniques From glaciers to arid plains for 1,800 miles, the great trans-Himalayan river is one of the world's longest, and the Indus's annual flow of 272 billion cubic yards is twice that of the Nile River and three times that of the Tigris River and Euphrates River combined. The Indus River's name comes from the Sanskrit word sindhu (river) and was the basis for the words India and Hindu. The Indus River has proved crucial not only to human history, but also to present-day life on the subcontinent. Today, the Indus is considered Pakistan's most important river, as it runs almost the entire length of the country and flows through all of its provinces except for the southwestern region. Like Egypt and Mesopotamia, these ancient people farmed with irrigation systems, maintained by silt-bearing floods. 2. Agriculture and Population The Indus civilization spread over a large part of modern Pakistan and northwest India. Settlements were found that dated back to 2800 BCE; between 2600 and 2500 BCE, a great social change occurred. Urban centers that had not existed before came into being. The people survived on a mixed agricultural economy. They grew barley and wheat, with possible evidence of rice cultivation as well. They also cultivated chickpeas and field peas. The fruits and seeds of various wild plants were also gathered, including grapes and jujube. Some of the earliest known use of cotton dates to the Indus River valley. In addition, the people of the Indus valley raised a species of humpbacked cattle. They also domesticated sheep, goats, pigs, and dogs, and chickens. Fish were an important part of their diet, and evidence indicates that urban centers near the sea traded fish to inland centers. 3. Greater political, social, and economical organization and complexity Trade played an important role among the Harappan people and they had trading relations with the people of Central Asia. Raw products, like gold, silver, and copper, and various minerals and precious stones were obtained. They produced metal products, such as copper goods, and ceramics and pottery. Information about trade with the people of the Persian plateau is uncertain, but a thriving trade was carried on with the cities of Mesopotamia. Products sent to Mesopotamia included agricultural goods and carved stones and different artistic items, including statues. 4. Discoveries and writing The hieroglyphic writing of the Indus valley people remains undeciphered (unknown). Archaeologists have studied the drawings that have been recovered, however, and have developed theories about the religious life of the people. Tim Watts Watts, Tim. "Indus valley civilization." World Geography: Understanding a Changing World.ABC-CLIO, 2011. Web. 23 Mar. 2011.