The pharaohs worshipped it as a god, the eternal bringer of life. But the clock is ticking on the Nile.
Human-driven climate change, pollution and exploitation are putting existential pressure on the world's second-longest river, which half a billion people depend on for survival.
All along its 6,500-kilometre (4,000-mile) length, alarm bells are ringing.
From Egypt to Uganda, AFP teams have gone out on the ground to gauge the decline of a river that drains a tenth of the African continent.
At its mouth on the Mediterranean, Sayed Mohammed is watching Egypt's fertile Nile Delta disappear. In Sudan, fellow farmer Mohammed Jomaa fears for his harvests, while at its threatened source in Uganda, there is less and less hydroelectric power for Christine Nalwadda Kalema to light her mud and wattle home.
"The Nile is the most important thing for us," said Jomaa, who at 17 is the latest generation of his family to work the river's rich banks at Alty in Gezira state.
"We certainly do not wish for anything to change," he said.
But the Nile is no longer the unperturbable river of myth. In half a century its flow has dropped from 3,000 cubic metres (10,600 cubic feet) per second to 2,830 cubic metres.
Yet it could get much, much worse. With multiple droughts in east Africa, its flow could fall by 70 percent, according to the United Nations' most dire predictions.