The earliest civilization of India in the valley of the Indus River were known as the Harappan Society, after Harappa, a major city which has been identified in the area. For some unknown reason, the people are commonly referred to as Dravidian. Little is known about them, including what they called themselves, as much of the artifacts of the civilization are buried under water; plus historians and archaeologists have not yet been able to decipher their language. For that reason, the names/titles given to the civilization are modern contrivances. It is known that they had a fairly sophisticated culture with streets and cities built on a grid. It is also widely believed that the culture declined due to their removal of trees and forest thus causing erosion of the soil. Eventually Indo-European peoples who called themselves Aryan ("noble people") moved into the area, and eventually absorbed the remains of the Dravidians. Aryan society has been more well documented and apparently has had more of an effect on modern Indian culture than has the Dravidian.