River - A large natural stream of water flowing in a channel to the sea, a lake, or another stream.

The World's Longest Rivers

1. Nile - 6,650 km (4,135 miles) - Africa - Drains: Uganda, Tanzania, Kenya, Rwanda, Burundi, Egypt, Democratic Republic of Congo, Ethiopia, Eritrea, and Sudan.

2. Amazon - 6,400 km (3,980 miles) - South America - Drains: Peru, Brazil, Guyana, Bolivia, Venezuela, Colombia, and Ecuador.

3. Yangtze - 6,300km (3,917 miles) - Asia - China.

4. Missippi-Missouri - 6,275km (3,902 miles) - North America - USA.

5. Yenisei-Angara-Selenga - 5,539km (3,398 miles) - Eurasia - Russia and Mongolia.

6. Huang-He (Yellow River) - 5,464 km (3,398 miles) - Asia - China

7. Ob-Irtysh - 5,410 km (3,364 miles) - Euraisa - Russia, Kazakhstan, China, and Mongolia.

8. Congo-Chambeshi - 4,700 km (2,922 miles) - Africa - Rwanda, Burundi, Zambia, Cameroon, Tanzania, Republic of the Congo, Democratic Republic of the Congo, Angola, Central African Republic)

9. Amur-Argun - 4,444 km (2,763 miles) - Eurasia - Russia, People's Republic of China, Mongolia.

10. Lena - 4,400 km (2,736 miles) Eurasia - Russia.

It is disputed whehter the Amazon is actually longer than the Nile; for more informaiton on this debate see here.