The longest something in the world?

The scientists claim to have traced the river's source to a snow-capped mountain in southern Peru, adding a new twist in the swirling debate over the longest river label.

Determining the length of a river is tricky because scientists have to pinpoint both where the river begins and ends, Andrew Johnston, a geographer at the Smithsonian's National Air and Space Museum in Washington, D.C., told National Geographic News.

"The mouth of the Amazon is so wide, it's hard to pick the exact spot at which to choose the end point with that kind of precision," he said.

"Personally, I would want to know a little bit more about how they came to that number before I was comfortable saying, 'Yes this is longer,'" he added.

--- this is far from clear evidence of the Amazon being longer than the Nile. Especially when there are numerous other references that say otherwise.