Hopefully with a big bang and no one feels a thing.
When people become extremely bad, when there's no good person in the world, and when the God gets angry.....then the world will go BOOM and he will destroy everything!
I don't think the world 'll end, whenever it is, it 'll never end, but on the contrary, we 'll die, it depends on our health, if we are healthy then we can live as long as we can, anyway, we can't see the world end, it 'll never end, whatever it happens.