The Congo River, also known as the Zaire River, is the largest river in Western Central Africa. Its overall length of 2,922 miles makes it the second longest in Africa, after the Nile River. The river and its tributaries flow through the second largest rain forest area in the world, second only to the Amazon Rainforest in South America. The river also has the second-largest flow in the world, behind the Amazon, and the second-largest drainage basin of any river, again trailing the Amazon; its drainage base is slightly larger than that of the Mississippi. Because large sections of the river basin lie above and below the Equator, its flow is stable, as there is always at least one river experiencing a rainy season.