It is one of the longest rivers in the world. There have been different studies that have tried to measure its exact length. As the studies have come up with different numbers, it is therefore difficult to give an exact number. The length also changes in the rainy season. Several studies from Brazil, Spain and Chile say it is the longest river in the world, longer than the Nile. The Nile has a length of . The Amazon may have a length of . The Spanish daily newspaper El País gives its length at . In 2007, scientists from Peru and Brazil calculated a length of .