Multiverse: One Universe or Many?

It is 8 o'clock. Do you know where your Universe is? She begins by imagining a tropical lagoon. For the fish that live here, this aquatic world is all its reefs. This lagoon is your entire Universe. They have no idea that there is something beyond. Well, they're fish... and yours is actually just one of a large number of bodies of water on the Earth's surface, some similar to yours and some very different. So now that you're a fish, how about you include that this world of ours is just a small lagoon in something much bigger? Could your fish brain handle that?

We only think that a single Universe once existed 14 billion years ago