What does this number measure?
The Nile includes the White Nile and Blue Nile joining at Khartoum, then crosses Egypt's valley and delta before reaching the Mediterranean. The 6 650 km reference follows a convention for the source branch and route. The Nile and Amazon systems do not have a single length independent of measurement choices; no certain record is claimed here.
This length follows the course adopted by the catalogue. Maps show simplified, sometimes partial courses; an independent bar represents the documented length, distinct from straight-line distance.
Compare the stated dimensions
The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.
Source and limitations
Length depends on the source branch, route and mouth boundary; a rounded value that alone cannot settle a comparison with the Amazon.
Top-down view of a simplified geographical route of the Nile, based on the available mapped segments. The reference drawing may be partial, and river systems may combine several branches. The river’s width and the water and bank textures are interpreted; this is not a satellite photograph. Only the lower bar represents the documented reference length; the width of the map above does not measure that length. Route: Natural Earth, public domain. Licence: Public domain.