These are the four "main cities" with the strongest power in the Human Federation.
The population of each city exceeds 300 million.
The total population of many medium and small countries in the world is only tens of millions, not even a hundred million.
So you can imagine, what concept is a "city" with a population of 300 million?
As long as you can settle in the Sixth-level Self-looping City, even if a mythical adversary comes, there is absolutely no need to worry!
Because any of these four cities alone can easily crush a world superpower, a strong race in combat power.
Apart from Infinite City, the other three main cities have all had achievements of "Godslayer" in history, having truly killed mythical creatures!
But it doesn't mean Infinite City has no combat power.
It's because Infinite City was built later, only appearing a few thousand years ago, so it hasn't had the chance to act until now.
