Satellite images reveal that the river bed I'm standing in is just one of a network of past river valleys that crisscrossed the Sahara desert. Ten thousand years ago, this dry, empty place was entirely different. Little is known about the early Saharans who lived here then, but we do know that they depended entirely on water. Water formed the lakes in which they swam. Water nourished the plants which fed the animals they hunted. Water filled the clay pots from which they drank, but then the climate changed. 

 

About five and a half thousand years ago, the Sahara began to dry. The rains failed, the river shrank and the lakes dried out. For the early Saharan people, there was only one option - to follow the rains and abandon the desert.

 

The fortunes of the early Saharan people revealed a universal timeless truth: our fate is inextricably linked to water. The problem is the water never stands still. It's always on the move across the planet. We think of this as a blue planet, but while water is abundant, most of it is no use. More than ninety-seven percent of the earth’s water is salty ocean which we can't drink or use to grow crops. Less than three percent is fresh water on which all human life hangs. What's more, that tiny fraction is often hard to depend on, because fresh water has a life cycle all of its own. 

 

The water seems so familiar, doesn't it? But to see its remarkable qualities, you have to go to some extreme length.