A quipu, or knot-record (also called khipu), was a method used by the Incas and other ancient Andean cultures to keep records and communicate information. In the absence of an alphabetic writing system, this simple and highly portable device achieved a surprising degree of precision and flexibility.
The Nile river is in Africa and The Mississippi river in U.S.A. The Amazon river is also 4,086 miles so close to 4,000. Plus the Amazon river is in South America and Brazil is in South America.
