Mohenjo-daro, once the big cheese of the Indus Valley Civilization, was rocking from around 2500 to 1700 BCE with a massive population of 40,000 peeps. But then, bam! Things took a mysterious turn ...

First transmitted in 1957, Sir Mortimer Wheeler describes the results of his excavations of the 4,000 year-old, red brick Indus Valley civilization city of Mohenjo-daro in modern-day Pakistan.

The cities became overcrowded, with houses built on top of houses. Important buildings like the Great Bath at Mohenjo-Daro were built over. People stopped maintaining the drains and they became ...