Obligatory apologies for formatting, on mobile.

For context, my friends and I have recently started playing D&D and I wanted to know how a city... well, becomes a city.

How does an area/location become settled, and eventually grow into a town or city? What features are necessary for a place to be settle-able (I'm guessing water is a big factor but what else)? How did current (or past) existing cites come into existence and spread out?

Alternatively, are there any books i should read about the birth and development of cities/towns?