Blue Nile

Blue Nile, also called Bahr-al-Azrak, is one of the two chief tributaries of the Nile, the longest river of Africa. The Blue Nile river rises from Lake Tana in northwestern Ethiopia. It flows south about 500 miles (800 km) in Ethiopia and then 400 miles (650 km) northwest into Sudan, where it meets the other principal headwaters called White Nile at Khartoum, after traveling about 900 miles (1450 km).