Mohenjo-daro

Mohenjo-daro, located in present-day Pakistan, was one of the largest cities of the ancient Indus Valley Civilisation, home to an estimated 40,000 people around 2500 BCE. The city featured a sophisticated grid street layout, a large public bath (the 'Great Bath'), multi-storey brick buildings, and an advanced drainage system that was among the world's first urban sanitation networks. The Indus script found on thousands of seals and tablets has yet to be fully deciphered, making Mohenjo-daro one of history's greatest unsolved puzzles.

Population estimates range widely; some scholars suggest 20,000–40,000 or higher. The city's sudden decline around 1900 BCE is not fully understood.

Context

Mohenjo-daro lies in Sindh province, Pakistan, and was occupied roughly between 2600 and 1900 BCE. It was rediscovered by archaeologists in the 1920s and became one of the key sites for understanding the Harappan, or Indus, civilisation. UNESCO listed the ruins as a World Heritage Site in 1980.

Population figures are inferred, not counted. Researchers estimate numbers from the size of the built-up area, the density of houses and comparison with later cities, and only part of the site has been excavated. Because large areas lie buried or have been damaged by flooding and rising groundwater, any single figure should be treated as a rough guide.

The city's decline is debated. Older theories blamed invasion, but most modern scholars favour gradual causes such as shifting rivers, changing monsoon patterns and weakening trade networks, and the evidence for a sudden catastrophe is thin. The ruins are made of fired and unfired brick and face ongoing conservation challenges from salt and water.