Existence of God?

And how exactly would the world get to that point other than killing everyone who believed in something? Changing people's minds isn't easy, because for most people religion isn't about dogma, but about a personal relationship with their God or Gods. Personally, I don't think my religious beliefs keep me from living personally with anyone. Since my Gods don't tell me to go around telling other people to worship them, I happily live with my own beliefs while letting others choose their own beliefs too. I think the idea of a religion-free society in the name of peace is interesting, but I don't think it would ever work. I think the thing you are overlooking here is that most people don't think of their deity or deities as far-away concepts, but as actually loved ones. It's like asking every single person in the world to abandon their own parents, and it's simply not going to happen.