The beggining of the Egyptian Empire

Seven or eight thousand years ago, at the farthest reaches of human memory, before there was Egypt or the pyramids, North Africa was a lush and green place. There were vast grasslands and green forests stretching from the Atlantic Ocean to the Red Sea. Over this enormous green area, humans wandered in small groups; eventually, about eight thousand or so years ago, some of these small groups began to plant and cultivate their food. You might say that this change, which happened so slowly that it probably took a millennium to take place, was the single most important event in human history. It turned humans into agriculturist s. As farmers, these wandering human groups settled down in one place, and human culture, confined now to villages, radically changed shape.
This revolution, so vital to everything that follows, took shape so slowly that at least one quarter of written human history can be contained in the period of time that it took for humans to become agriculturists. While this revolution happened all around the world, North Africa was a special case.
For about the time humans slowly transformed into farmers, North Africa started to die. It died slowly and imperceptibly, but generation after generation began to notice that it was raining less frequently and that there were fewer plants. The death of the grasslands and forests slowly gave way to sand; in a few thousand years, North Africa became "The Desert" ("Sahara" means "desert" in Arabic). Humans were pushed relentlessly by the encroaching dry and sand. They were pushed south (they are still being pushed south as the Sahara continues to grow), some were pushed north into the Middle East, and some were pushed towards the Nile River. Like a solitary giant, the Nile loomed as the only source of water in the growing desert; in a sea of sand, the Nile was a thin sliver of green, growth, and life.
This is where the great Nile civilizations were fostered and grew: Egypt, Nubia, and Meroe. From the desperate human communities forced by the growing desert to live on the banks of the Nile grew one of the first great urban cultures of human history.