The Congo river is the second longest river in Africa, after Nile, as well as the second largest river in the world by discharge volume, following only the Amazon. The Columbia river is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada. The Yangtze river is the longest river in Asia, the third-longest in the world and the longest in the world to flow entirely within one country. It rises in the northern part of the Tibetan Plateau and flows 6,300km in a generally easterly direction to the East China Sea.