Town-planning

Harappa and Mohenjo-daro, now in Pakistan, were the first two cities of this civilisation to be discovered, about a century ago. Several more sites were then found in the Indus plains, which is why it was first called the 'Indus Valley civilisation'.

Later, other major cities were found, such as Dholavira in Gujarat, Rakhigarhi in Haryana and Ganweriwala in the Cholistan desert of Pakistan, along with hundreds of smaller sites such as Lothal in Gujarat. Discoveries are still being made today!

The bigger Harappan cities were built to precise plans. They had wide streets, often laid out along the cardinal directions (north–south and east–west). That means someone planned the whole city before the houses went up.

Most cities seem to have had a fortification (a massive wall round the city, usually for protection) and two parts: the 'upper town', where the local elite probably lived (rulers, officials, administrators and often priests), and the 'lower town', where common people lived. Dholavira is different: it had three zones, and there most foundations were made of stone.

Some large buildings were probably used by everyone, for example warehouses, big store rooms where goods waiting to be transported were kept. Houses of different sizes lined the streets and lanes. And here is the sentence B.B. Lal built his judgement on: the quality of building was the same for small and big houses, mostly of bricks. Rich and poor had houses of different sizes but the same workmanship.

The purpose of some buildings is still debated, such as the famous 'Great Bath' at Mohenjo-daro. It is a small but carefully made tank, about 12 × 7 metres, waterproofed with natural bitumen (a kind of tar) over carefully laid bricks. Small rooms surrounded it, one with a well, and a drain in one corner let it be emptied and refilled with fresh water.

What was it for? Archaeologists have suggested a public bath, a bath for the royal family only, or a tank for religious rituals. The first idea is now ruled out, because most houses in the city had their own bathrooms. And for this question we have no other source: no inscription, no text, no traveller's account.