The city was once inhabited by humans.
- This is why they have things like toilets and kitchens that are of no use to robots. The city was built for humans, with the robots as helpers, entertainers, companions, etc. Eventually, the humans polluted so much, that they died out, and only robots were left. Fortunately, the creator of the robots foresaw this, and implanted his consciousness into a robot body, becoming the Mayor. This is why the Mayor has such a huge head, and is wired down, so he cannot move. Robots holding human consciousness was such a new technology, that there was no way to do it wirelessly, and the examples of such technology were huge and unwieldy, like old computers.
The city is one of the four cities from Primordia.
- Both games take place in a post-apocalyptic setting devoid of humans, with robots that evolved into their own culture. Not only that, but both have semi-futuristic cities with several robots appointed to lead them, complete with a tall tower in the middle where the leader(s) work, connected by monitors and wires to the rest of the city. It's possible that the absence of humans was caused by the War of the Four Cities that completely annihilated every human on earth, leaving the remaining robots to fend for themselves in search of energy and shelter.