After the Catastrophe, People All over the World Live in One Building

[No system + doomsday + wasteland + cyberpunk, no Virgin, no heroine] "If you are reading this file, it means that you are either a high-ranking powerful person or a consumable that is about to be filled into the meat grinder at the bottom of the nest as biofuel. In this super building that accommodates 300 million people, Remember the only rule: don't look up, there are no gods there, only barbarians who treat you as food. " This is a super shelter built after the "Great Reckoning" disaster, or a vertical folding hell.