The largest river basin in the world is the Amazon Basin, which covers approximately 7 million square kilometers. This basin encompasses the majority of the Amazon Rainforest and includes multiple countries, primarily Brazil, along with parts of Peru, Colombia, and others. The river system is vital for biodiversity and is home to numerous species. The Amazon River, flowing through this basin, is noted for being the second longest river globally. Its vast network of tributaries plays a crucial role in the hydrology of the region and supports both human livelihoods and ecosystems.