image source
The history of the humanity was divided into to kinds of eras, the first one is the prehistorical eras and it was before man know writing. During this period man used to live on highlands looking for food and water. Of course because he didn't know writing he couldn't register any thing so we don't have any kind of readable history and we knew about them only from their remains since millions of years ago. We must mention that they made all their stuff from stone and that's why they called it the stone eras.
image source
The ancient Egyptians lived a very hard life during this time. and because of dryness on the highlands they couldn't live any more there and they were obliged to come down and live in the Nile valley. And this was a turning point in the history of the Egyptian civilization, because they began to live in stability, built small houses and consisted families and they learnt agriculture instead of looking for food. Of course at that time they knew the hieroglyphic writing and began to register all the aspects of their life and all the advances they achieved in different fields.
image source
image source
image source
And this was the beginning to establish the magnificent and majestic Egyptian Civilization that fascinated the whole world.