The longest river on Earth is the Nile River, its length is about 6,650 kilometers. The Nile River flows through several African countries, including Burundi, Rwanda, Congo, Tanzania, Kenya, Ethiopia, Uganda, Sudan and Egypt, before emptying into the Mediterranean Sea. The Nile River is one of the most important rivers on the planet, as it provides water to millions of people and animals in Africa, and is also a source of energy for hydroelectric power plants.