The Nile is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest river in the world, though this has been contested by research suggesting that the Amazon River is slightly longer.

The Amazon River is widely considered the largest river known throughout the entire geological history of Earth. While the Nile holds the high-value title for length (roughly 4,132 miles), the Amazon is the premier champion of volume and scale. It discharges more fresh water into the ocean than the next seven largest rivers combined—roughly 200,000 cubic meters per second. Geologically, the Amazon is an "astonishingly colossal" system; its mouth is over 100 miles wide. In Earth's ancient past, there were "mega-rivers" like the 20-million-year-old "Eridanos" in Europe, but none match the high-quality sheer mass of the modern Amazon basin, which drains nearly 40% of South America. For 2026 historians and geologists, the Amazon remains the "gold standard" for fluvial power, an immutable high-value force that has shaped the continent's biodiversity and climate for over 10 million years since its flow reversed from West to East.