answer:Almost no disease could actually destroy the world—it would be hard to top, say, the plague—though they could do a lot of damage. No to particle accelerators too. I think the “gray goop” prospect of nanotechnology, i.e. that self replicating miniature robots just keep replicating and eat everything, is the creepiest sci-fi scenario that has a tiny chance of happening. But truthfully, we’re much more likely to go through climate change or a nuclear exchange.