Harappa is a large village presently in the province of Punjab in Pakistan. ... The site of Harappa is important in that it has provided proof of not just the Indus Valley Civilization as it was in its prime, but also of preceding and succeeding cultures as well and is the only site included in this category.
The Harappan Civilisation has its earliest roots in cultures such as that of Mehrgarh, approximately 6000 BC. The two greatest cities, Mohenjo-daro and Harappa, emerged circa 2600 BC along the Indus River valley in Punjab and Sindh.
Apparently the Indus civillization was likely destroyed by the Indo-European migrants from Iran, the Aryans. The cities of Mohenjo-Daro and Harappa were built of fire-baked bricks. Over the centuries the need for wood for brick-making denuded the country side and this may have contributed to the downfall.
