The history of India begins with the birth of the Indus Valley Civilization (IVC), also known as Harappan Civilization. It flourished around 2,500 BC, in the western part of South Asia, in contemporary Pakistan and Western India. The Indus Valley was home to the largest of the four ancient urban civilizations of Egypt, Mesopotamia, India and China. In 1920s, the Archaeological Department of India carried out excavations in the Indus valley wherein the ruins of the two old cities, viz. Mohenjodaro and Harappa were unearthed. In 1924, John Marshall, Director-General of the ASI, announced the discovery of a new civilisation in the Indus valley to the world.
Three phases of Indus Valley Civilization are:
The Harappan culture was distinguished by its system of town planning. Harappa and Mohenjodaro each had its own citadel or acropolis, which was possibly occupied by members of the ruling class. Below the citadel in each city lay a lower town containing brick houses, which were inhabited by the common people.