The Indus Valley Civilization began around 2500 BCE in what is now Pakistan and northwestern India. Two major cities, Harappa and Mohenjo-Daro, each had populations of around 40,000 people and were carefully planned with grid-like streets and drainage systems. The civilization engaged in extensive crafts and trade, producing goods from materials from distant regions. While much remains unknown without a translation of their language, the archaeological record suggests an advanced, organized society without obvious social stratification.