Indus civilisation: Harappa and Mohenjo-daro

The Indus or Harappan civilisation built some of the world's first planned cities, with grid streets, brick drains, granaries and public baths, and traded its stamp seals as far as Mesopotamia. Harappa, excavated from the 1920s, gave the culture its name. Its script is still undeciphered, and why the cities emptied after about 1900 BC is still debated.