
56k warning
Diana Wynne Jones actually had a thing like this, her books are set in this multiverse with interconnected rings of worlds where each world in a ring has a similar history to each other, and it's repeatedly established that the world most of her books are set in* is right next to "ours" in a ring, with the split point in our history being that everyone started thinking so rationally that the gods all died and magic stopped working**
* Harry Potter***
** Which actually kind of means you can't travel to or from our world, because you need magic to travel between parallel universes
*** No really. Harry Potter is basically a total ripoff of the "Crestomanci" books.