The correct answer to this open question is the following.
The Indus River Valley Civilization was isolated from the outside world due to the geographic features in which it was located. Basically, next to the Indus River. They were known as the Harappa civilization and settled in modern-day Pakistan. The two most important cities of the Indus Valley were Harappa and Mohenjo-Daro.
Historians think that two factors influenced the disappearing of the Indus Valley civilization. One is climate change. The other, the ib¿nvasion of a tribe called the Aryans, an Indo European tribe who were nomads. The decline of this civilization started in 1800 BCE.
