They called Mohenjo Daro, the Mound of the Dead.
For almost four thousand years the hills near the Indus River in modern-day Sindh, in Pakistan, kept their secrets. The local villagers avoided the place, they said anyone who climbed the highest mound at night would wake up the next morning with blue skin, a mark of the angry spirits that guarded the ruins. Children were warned never to play there. And even British surveyors in the 19th century marked the spot on their maps and moved on.

