Ancient Egyptians saw their country as "Two Lands". Kemet, the Black Land, was the name given to the fertile area near the river, and Deshret, the Red Land, referred to the desert. The ancient Egyptians believed that their country had once been two separate states: the Delta in the North; and the Nile Valley, to the South. Because the Nile flows from its central African origins upstream in Ethiopia and Kenya, downstream to the Mediterranean, we call the Delta Lower Egypt, and the Valley Upper Egypt. One of the most common titles of the pharaohs was King of Upper and Lower Egypt.

The Nile has always been the lifeblood of Egypt. Boats could sail from the Southern boarder at Aswan, all the way to the Mediterranean in about three weeks. Communication of all sorts, trade, religious and social ideas, and political organization travelled along the River. The Nile was filled with fish, and shore birds crowded its banks.

Even more important, from the most ancient times until the Twentieth Century, the Nile flooded annually, depositing on fields along the river a layer of silt washed down from the highlands of Ethiopia. Every year, fields were enriched by new soil; this helped Ancient farmers to grow rich crops without additional fertilizer.

The Annual Flood also flushed pollutants and salts from the soil, keeping it fertile for thousands of years. Fruits, vegetables and grain grew abundantly in the black soil, and cattle grew fat along the banks and in the Delta. Large numbers of trees, among them acacia, sycamore figs and date palms, provide shade, food, and fibres to make ropes, mats and clothes. In the past, these trees were also very important sources of building materials and fuel.

Although Egypt is still, as the Greek traveller Herodotus said, the Gift of the Nile, there have been important changes during this century. During the last hundred years, a series of dams have been built on the Nile. They regulate the flow of water, so that more land can be put under cultivation. They also even out the amount of water available every year, so that farmers no longer have to worry whether the Nile flood will be too high, and wash away their fields, or too low, so that not all the land can be irrigated.

The High Dam at Aswan, completed in the 1960s, put an end to the yearly inundation, while providing Egypt with hydroelectric power. Behind the dam, an enormous permanently flooded area, called Lake Nasser, has become a major source of fish.

Lake Nasser has affected the climate and ecology of the whole valley. There is more rain than in Ancient times, and the water table is higher. The annual flood no longer flushes pollutants and salts from the land, and this has led to some damage to arable land as well as ancient monuments. Without the annual addition of new soil, the Delta is getting smaller, and the reduction in nutrients reaching the Mediterranean has reduced the size of the fishery.