The year is 2676, the new period is called "Pollution era". Everywhere you see, it is filled with behemoth, and HUGE nuclear power plants fills the land. The "oxygen" is 20% real natural oxygen and 80% from smog and thick fog from the smoke of the nuclear powerplants. You see mostly vast concrete steel sky high skyscrapers that engulfs mountains with their mass, the buildings are very concentrated as storing storage for building materials, workers, warehouse, etc.

But since everyone is also very sedentary due to the working, everyone is 350lbs+ or heavier...