the longest river in the world

Did you know that the longest river in the world is the Nile? Egypt's greatest river is 4,135 miles long! In fact, Africa has two of the ten longest rivers. The Congo, which flows through central Africa, is Number 8 at 2,914 miles long.
What's the second longest river? Why, the Amazon, of course! It is about 4,000 miles (3,980, really) from start to finish, winding its way through most of South America.
China lays claim to Numbers 3 and 6: The Yangtze River is 3,917 miles long, and the Huang He is 3,395. North America's longest river, the Mississippi and Missouri combination, comes in at 3,870 miles long.
How do we measure these rivers? Geographers calculate the distance from the source of the river to its mouth. For instance, the Ob-Irtysh River, which is Number 7 on the list, is 3,354 miles long from its source in southern Russia to its mouth in the Ob Bay, in the very cold waters off northern Russia.
Russia has three more rivers in the Top Ten. Number 5 is the Yenisie River, which flows through Siberia and is 3,440 miles long. The Amur River runs through northeast Asia and totals 2,744 miles in length. The Lena River, at Number 10, flows north through central Russia and is 2,728 miles long.