It was one of the main environmental factors that helped them achieve a sense of sustainability. It is their source of existence. The river helped the region cope with the fact that it is overwhelmed by desert land and from then on a very dry climate. The reason is that the Nile tended to flood every year, but in a way that eventually allowed the land and land to be suitable for agriculture. Egypt as a whole also has three supposedly “defensible” borders. The east, west and south consist of links between suitable and strong terrains. The north, which includes the Nile Valley, is full of deserts and is therefore unsuitable for defenses to walk along/between them. In contrast, Mesopotamia was vast and open, with fewer borders. Mesopotamia is bordered by the Tigris and Euphrates rivers. Their flow of water provided sufficient nutrients to the land and the people around it. There was no regular cycle of flooding like the Nile; however, whenever flooding occurred, massive destruction occurred. Mesopotamia also has mountains which are unfortunately seen as one of its weak points. The routes along these mountains allowed attacks and invasions on civilizations. For this reason there was a lot of influence from outside; therefore, Mesopotamia consisted of different types of cultures and people, such as Sumerians, Elamites, Mittanni, and many others. While in Egypt, although not entirely monolithic, it was made up of the majority of Egyptians