Ruins of Harappa, one of the earliest cities of the Indus civilization, ca. 2600 BC.
Note the small size of individual rooms and the narrow width of passageways. Through this method it was possible to fit a large number of people into cities built from single-storey houses.
Although the cites were packed with people it was always possible to find relief from the crowds by taking a short walk - the surrounding countryside was always within easy reach.