The Indus Valley Civilization was one of the world's first enormous urban civilizations. It flourished in the vast river plains and contiguous regions in what are now Pakistan and western India.
The earliest cities became incorporated into an far-reaching urban culture around 4,600 years ago and continued to overlook the region for at least 700 years, from 2600 to 1900 B.C. It was only in the 1920's that the buried cities and villages of the Indus valley were accepted by archaeologists as representing an undiscovered civilization.
This untimely beginning led to the meditation of population into the small towns, such as Kot Diji in Sindh and Rahman Dheri in Dera Ismail Khan district. It is this social and cultural exchange that led to the rise of the famous cities of Moenjodaro and Harappa, with largest concentration of population including artisans, craftsmen, businessmen and rulers.This culminated in the peak of the Indus Civilization which was primarily based on intensively irrigated agricultural land and overseas trade and contact with Iran, Gulf States, Mesopotamia and Egypt. Dames were built for storing river water, land was cultivated by means of bullock-harnessed plough - a system which still prevails in Pakistan, granaries for food storage were built, furnace was used for controlling temperature for making red pottery and various kinds of ornaments, beads of carnelian, agate, and terracotta were pierced through and above all they traded their finished goods with Central Asia and Arab world. It is these trade dividends that enriched the urban populace who developed a new sense of moral honesty, discipline and cleanliness combined with a social stratification in which the priests and the mercantile class dominated the society. The picture of high civilization can be gathered only by looking at the city of Moenjodaro, the First Planned City in the World, in which the streets are aligned straight, parallel to each other with cross streets cutting at right angles. It is through these wide streets that wheeled carriages, drawn by bulls or asses, moved about, carrying well-adorned persons seated on them appreciating the closely aligned houses made of pucca-bricks, all running straight along the streets. And then through the middle of the streets ran stone dressed drains covered with stone slabs - a practice of keeping the streets clean from polluted water, seen for the first time in the world.