Answer: Amazon River
Notes: The Negro River, a main tributary of the Amazon, recently dropped to its lowest level in 122 years. It is one of the largest tributaries of the Amazon River and one of the world’s largest rivers by discharge. Originating from eastern Colombia, it flows through Colombia, Venezuela, and Brazil before joining the Amazon at Manaus. The river spans about 1,400 miles, with 850 miles in Brazil. The river was named "Negro" for its dark water due to decomposed organic matter and tannins. It is the world's largest blackwater river. The Central Amazon Ecological Corridor, a giant protected area, surrounds it.
