Then, in 1971, a National Geographic expedition led by Loren McIntyre identified the snow-capped peak of Mismi (map) as the headwaters of the Apurímac River and the ultimate source of the Amazon.

In 1846, according to the atlas “Maps of Useful Knowledge,” the Amazon was the world’s longest river, at 3,200 miles; the Nile came in at 2,750. More recently, Brazilian researchers have ...

The Negro River drains about 10 per cent of the Amazon basin and is the world's sixth-largest by water volume. Manaus, the biggest city in the rainforest, is where the Negro joins the Amazon River.