Experts have established that the foundations of this civilization in India were laid during the Bronze Age that followed the Neolithic Age. The remnants of it were first unearthed from Mohanjo-Daro, in Sindh and Harappa in Multan both in what is now Pakistan, and also from Lothal and Dholavira in Gujarat and Rakhigarhi in Rajasthan, both in the India of today. It has been called the Indus Valley Civilization, for it was first thought to be of the area networked by the Indus and its tributaries. But later on it was found that this highly developed civilization of urban nature, endowed with the art of writing and arts such as dancing, extended even beyond the valleys of the Ganges and the Yamuna.
Where did this superior culture emerge? From Sumeria or from Egypt where similar cultures existed almost at the same time? But the Indus Valley Civilization was far more advanced than the Sumerian or the Egyptian civilizations, as is seen from its city plans with farm houses with thoughtful facilities like ablution tanks, figurines of a dancer girl indicating the level of artistic pursuits, and the script of the language etc. John Marshall who piloted the excavation of the sites in India was of the opinion that the people worshipped Shiva of the Dravidian culture. Linguists have opined that the scripts as seen in the seals indicated a relationship with the early Dravidian family of languages, if not the very proto-Dravidian language, for re-constructing which great scholars have toiled for years. However, attempts at deciphering the script have not yet been successful.
Civilizations have been found to decline and disappear for various reasons like the invasion from a superiorly strong foreign force, the depletion or destruction of sources for food and water as from floods or drought, the spread of some contagious disease, the change in the course of a river or a more catastrophic fault or shift in the surface structure of the land due to tectonic movement. And one of these or a combination of more than one factor might have caused the end of the Indus Valley Civilization. But the question remains as to how a civilization which had spread to a vast area of different river systems and different topographic features ended altogether.