Recently I was reading about tunneling experiments showing faster-than-light tunneling effects, and commentary that it should be impossible for them to be FTL, as this would contradict special relativity. In the context of simultaneity being 'relative' in SR, it would cause the paradox of being able to change the past. So I looked in to the "relative" notion of simultaneity, and something looks very odd to me: If there is event A at location A, and events B1 and B2 at location B, where B2 occurs after B1 for a stationary observer at location B : Now, for observer O1, event A might be simultaneous with event B1, while for observer O2, event A might be simultaneous with event B2. The funny thing seems to be, relativity theory doesn't seem to just say that it looks that way, but that it really is that way. But wouldn't that mean that when event A occurs, both events B1 and B2 would have to exist both at the same 'time', so to speak? "Multiple worlds" already in relativity theory?