I have discovered that whenever I take daytime naps, I end up visiting parallel Universes, they are very similar to this world with minor differences. The thing that assured me that it is not just a 'dream' is that the similar events happening on this reality also happens on those other realities simultaneously, it is usually the same time, and I would be with the same people who are on that location but doing things differently.

Remember one of those dreams when you were a kid, It's the morning you dreamt you have woken up, you are already in school, but suddenly your mother wakes you up, then you realize that you are still in bed. In these experiences, you have actually visited parallel Universes without knowing.