From Wikipedia

Egypt - The Quest For The Lost World

The Nile, an unending source of sustenance, provided a crucial role in the development of Egyptian civilization. The Nile made the land surrounding it extremely fertile when it flooded or was inundated annually. The Egyptians were able to cultivate wheat and crops around the Nile, providing food for the general population. Also, the Nile’s water attracted game such as water buffalo; and after the Persians introduced them in the 7th century BC, camels. These animals could be killed for meat, or could be captured, tamed and used for ploughing — or in the camels' case, travelling. Water was vital to both people and livestock. The Nile was also a convenient and efficient way of transportation for people and goods.

The structure of Egypt’s society made it one of the most stable in history. In fact, it might easily have surpassed many modern societies. This stability was an immediate result of the Nile’s fertility. The Nile also provided flax for trade. Wheat was also traded, a crucial crop in the Middle East where famine was very common. This trading system secured the diplomatic relationship Egypt had with other countries, and often contributed to Egypt's economic stability. Also, the Nile provided the resources such as food or money, to quickly and efficiently raise an army for offensive or defensive roles.

The Nile played a major role in politics and social life. The pharaoh would supposedly flood the Nile, and in return for the life-giving water and crops, the peasants would cultivate the fertile soil and send a portion of the resources they had reaped to the Pharaoh. He or she would in turn use it for the well-being of Egyptian society.

The Nile was a source of spiritual dimension. The Nile was so significant to the lifestyle of the Egyptians, that they created a god dedicated to the welfare of the Nile’s annual inundation. The god’s name was Hapy, and both he and the pharaoh were thought to control the flooding of the Nile River. Also, the Nile was considered as a causeway from life to death and afterlife. The east was thought of as a place of birth and growth, and the west was considered the place of death, as the god Ra, the sun, underwent birth, death, and resurrection each time he crossed the sky. Thus, all tombs were located west of the Nile, because the Egyptians believed that in order to enter the afterlife, they must be buried on the side that symbolized death.

The Greek historian, Herodotus, wrote that ‘Egypt was the gift of the Nile’, and in a sense that is correct. Without the waters of the Nile River for irrigation, Egyptian civilization would probably have been short-lived. The Nile provided the elements that make a vigorous civilization, and contributed much to its lasting three thousand years.

That far-reaching trade has been carried on along the Nile since ancient times can be seen from the Ishango bone, possibly the earliest known indication of Ancient Egyptian multiplication, which was discovered along the headwaters of the Nile River (near Lake Edward, in northeastern Congo) and was carbon-dated to 20,000 BC.