Thought Experiment.

What if ...

850,000 small cities with approx 10,000 people in each city?
Each city living in symbiotic harmony with the surrounding environment and cooperating and sharing with those nearby. All residents cooperating and sharing with each other.

As an alternative to giant megacities with millions of people all stacked on top of each other competing for jobs & other resources.

I can't visualize the habitable space on mother Earth, so I have no idea if this is even viable.

@falgn0n London's undergoing this, to some extent. The boroughs have become almost like their own miniature cities, with London acting as a city of cities.
@GreenandBlack
so the "thought experiment" is one of viability.
I guess we could put it another way: can that many of those cities be placed all around the globe, where and how far apart from each other? Remember, we're avoiding: people all piled on top of each other (so: spacious) and we want cooperation between cities (#moneyfree trade or sharing of some kind) . And we also want symbiotic harmony with the immediate environment for each of the cities.