Thousands of years ago, one man had an idea about how to harness the power of a river. Today, his legacy is still being celebrated https://on.natgeo.com/2H55cQG

Thousands of years ago, one man had an idea about how to harness the power of a river. Today, his legacy is still being celebrated https://on.natgeo.com/2H55cQG 

https://twitter.com/NatGeoTravel/status/982619093554683904