Q&A: What are the essential structures of a city?

Question by Neo: What are the essential structures of a city?
Im trying to model an interactive virtual city/town/community
populated by virtual people with simplified behaviors. Right now Im just concentrating on the essential structure/parts of a typical city so I can make a simplified,general template as a guide for building this environment.
To start, I listed some building block structures that center around human needs like food/energy, water, shelter…etc.
for example: structures related to…
food(grocery store, restaurant)
energy(electrical power plant)
water(water filtration plant)
waste management(sewer, waste processing plant)
shelter(residential house, hotel, apartment, office building)
transportation(pathway/ro… bridge, highway, vehicle factory, gas station, train station, airport)
health(hospital, dental office)
order/government(city hall, police station, fire station)
entertainment(movie theater, shopping mall, sports stadium, park)
learning(school, university, library, museum)
This list is still growing. I dont need to model complicated, realistic buildings. Simple, basic, primitive blocks/cartoon representations of the real things would suffice. Think lego city.

Any kind of info,idea,link,reference you want to share is welcome and appreciated. Thanks for helping.

Best answer:

Answer by makarim83
I think that the most important structures are the infra-structures like the bridges, miitary structures, etc …

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