Mohenjo Daro, Pakistan

Photo: Mohenjo Daro, Pakistan

The Indus Valley civilization was entirely unknown until 1921, when excavations in what would become Pakistan revealed the cities of Harappa and Mohenjo Daro (shown here).

This mysterious culture emerged nearly 4,500 years ago and thrived for a thousand years, profiting from the highly fertile lands of the Indus River floodplain and trade with the civilizations of nearby Mesopotamia.

Photograph by Randy Olson

Mysteries of the Ancient World