Contents 1. Geography 2. Culture 3. History The Nile near Juba, Sudan. The Nile passing through Khartoum, Sudan. The 4th Cataract near Karima, Sudan. The landscape of the 1st Cataract, at Aswan, Egypt. Scene from out on the Nile next to Assyut, Egypt. Agriculture next to Minya, Egypt. The Nile passing thrrough Cairo, Egypt.

Geography
The Nile can be divided into three zones, starting in the south: The first consists of tributaries to the two streams of the White Nile and the Blue Nile which join near Khartoum in Sudan. The second zone is the stretch between Khartoum and Cairo. The third and last zone is the Nile Delta, where the Nile divides into several branches and artificial canals. The main rivers are Rosetta (Rashid) and Damietta (Dumyat) are the main ones. The Nile Delta is the widest habitable area of the Nile, and it even includes several lakes, like Manzala, Buruillus and Edku.
The width of the Nile north from Aswan in Egypt — it's most important stretch in terms of inhabitants and economy — is 2.8 km in average. The greatest width is at Edfu, with 7.5 km, the smallest at Silwa Gorge, near Aswan, with 350 metres.
Modern times have added more division lines, like the two dams at Aswan. There are also minor dams in Sudan, aiding agriculture and protecting against large floods.
In the late 19th century, the Ibrahimiyya Canal was constructed, diverting water between Assyut, ending at Giza and Fayoum Oasis.
About 83% of the total water of the Nile comes from Lake Tana, 1,800 metres above sea level in the Ethiopian mountains. Lake Tana floods every summer providing for the flood that today is tamed by the barrages of Sudan and southern Egypt. This water flows through the Blue Nile until it joins the White Nile at Khartoum, Sudan to form the Nile.
The other main source is the White Nile originating in Uganda and Burundi. It contributes with 16%, but this is a more steady flow. Without it, the river Nile would run dry in May. As there are many single contributors to the White Nile, it is a question of definition on where the Nile really starts. The longest stretch of the Nile comes with the start of Kyaka river in Burundi, close to large Lake Tanganyika. This passage goes through Lake Victoria, then Victoria Nile, Lake Albert, Albert Nile, which across the Sudan border is called Mountain Nile. Mountain Nile joins other rivers of Sudan to form the White Nile.
The third notable contributor is the Atbara River, which joins the main course of the Nile 300 km north of Khartoum. Atbara River contributes with less than 1%, and runs dry at times of the year.
The Nile carries water all through the year, but the amount of water it carries, varies depending on the season. With the construction of Aswan High Dam, this is now controlled for Egypt's part. In ancient times, when agriculture depended much upon the water and the silt from the annual flood, the ideal flooding height was 7-8 metres. Less than that, and the produce was in danger. More than that, and the flood could cause major damage.
There are more dams than the one at Aswan, in Sudan the Blue Nile is dammed by Sennar Dam. The White Nile is dammed just before Khartoum. Both are important for local agriculture.

Culture
Around 105 million people live along the Nile, most of these in Egypt. The Nile has been the source of civilization for more than 5,000 years. The greatest of these civilizations belongs to Ancient Egypt. More recent, and less impressive, but still important was Nubia, belonging to the region of modern Sudan. This period lasted until about 0 CE.
Following that period, important cultures arose in Egypt. First was the Roman and Coptic periods, followed by a number of strong Muslim states. These include the Fatimids, the Ayyubids and finally the Mamluks. Since the 16th century, the cultures around the Nile have been weak and poor. Modern Egypt and Sudan are the poorest countries in North Africa and the Middle East, with enormous problems. Uncontrolled population growth of these two countries provide for bleak future prospect, even if the Egyptian economy has shown growth in the late 1990's.

History
6 million BCE: The earliest we know of a river through Egypt; scientists name it Eonile. This river ran through a canyon with walls that could be up to 3,000 metres high. There are indications that the Mediterranean Sea did not exist in this period. The source of Eonile is not known.
5 million: The waters of the Mediterranean Sea rises, filling up a basin reaching as far as modern Aswan. This brings an end to Eonile.
4 million: A second river starts flowing through Egypt, by modern scholars referred to as Paleonile. Its sources are believed to have been in equatorial Africa.
1.8 million: Dramatic climatic changes, causing the end of a water stream flowing north. Desertification in North Africa casues the emoty river canal to be filled with sand.
1.5 million: The third river, the Protonile, starts flowing through Egypt, creating many interwoven channels. The Protonile ran to the west of the modern Nile, through the region known today as Western Desert.
500,000: The Prenile replaces the Protonile, running further to the east, and starts carving out the river valley existing today. Its discharge was the largest ever for any of the Niles, before and since.
150,000 The Prenile starts to dry out.
30,000: The Neonile starts flowing through Egypt, basically following the same course as the modern Nile, but with a higher elevation.
8,000: The Neonile has carved itself down to the present elevation, and we can start talking about the Nile as we know it today.
1902: The Aswan Dam opens, allowing better control with the flow and flooding of the Nile through Egypt.
1960: The Aswan High Dam opens, allowing Egypt even better control with the flow all through the year, but removing the valuable silt which normally enriched the soil. A very important hydroelectric power plant is constructed here.