The world is based on thoughts. Every thought creates an existance, there for anything and everything happens as long as a person thinks about it. They create some what of a new reality, that can only be found through that persons thoughts. So a single person can create infinite realities, but they are different then another persons.
Now certain places in the Universe are connected, be it through Nirvana, thought or physiclly. These are connected realities, although none of them are together. They run through cycles, each differing then the last, but held together by some barrier.
There are very few places which are connected through all three planes. These places tend to be unstable, and unable to stay whole for a long period of time. In these places all the realities are connected, so if someone there thinks that an elephant is coming down the street, then the elephant is coming down the street for everyone, not that single person, and not after someone elses reality happens.
Once the connections of these planes breaks down, the place seems to go back to its former state, before it was connected. Although sometimes, it creates a twisted loop which, although changing slightly each time, goes through the same time as when it started.
If a person enters a place that is connected fully or partially, then they are put into that period, and their thoughts become real. They are then like one of the people stuck in this loop.