These places built their lives around these areas to help their society survive. Without the large amount of rivers and mountains these civilizations would not have survived. Protection, food, water and trade are just some of the things provided due to the geography of the areas. Some of these places were seen as religious guidance that formed some of the religions we have today. The societies would not have survived if it were not for these characteristics. There's no telling where our world would be if they didn't have them