If all out nuclear war happened, many places in the world could be wiped off the face of the Earth in the blasts. Unlucky survivors would die slowly from radiation or in nuclear winter. It’s a nightmarish scenario, and just one way humanity could be doomed. We could also be killed off by disease, environmental problems, and asteroids, just to name a few extinction level events. Because there are so many ways humanity could end on any given day, some people have built, or are in the process of building, some amazing bunkers and fallout shelters.