Equator's Wall
The line has been drawn, and you don't get to choose which side you're on.
An unbreakable, infinite glass wall manifests overnight along the equator, extending deep underground and far above the atmosphere. Air travel across the barrier causes immediate catastrophic crashes, forcing the International Space Station into strictly regulated northern orbital paths. World governments enact global protocols forbidding any attempt to cross the divide. The barrier splits the Earth into a literal good side and bad side: the top side (Northern Hemisphere) experiences miraculous fortune, including better economic conditions and cures to chronic illnesses, while the bottom side (Southern Hemisphere) suffers the worst possible outcomes, marked by severe virus outbreaks and economic collapse. Humanity is left stranded on opposite sides of a physical boundary that cannot be moved, dug under, or flown over.
