Why did cities develop near rivers?

Cities developed near rivers because:
1) source of water: rivers literally give you water that can be used for both drinking (if it is clean enough), bathing, irrigation, etc
2) trade route: rivers were used as trade routes during that time, as ships went up and down with goods
3) natural defense: if the river is large enough and fast-flowing, it can become a natural defense. However, this is not the case for many rivers

hope this helps