How to change map behind you

I was wondering how you can create the effect like in horror games where the map/scene changes behind you?

If you don’t know what I mean please watch a minute from this Batman Arkham Knight.(spoiler)

Thanks in advanced

There many ways to achieve this, i think the simple one is simply swamping peace of the level (mesh) that will direct you different path normally hidden. You can also apply level streaming in to this, which lat you load maps on top of existing map:

To trigger this you need to make sure player looks on specific direction, or force player to interact with something in specific orientation, like making player look on joker “going in” in your linked example. You can use line tracing for that

Or simply check player Yaw.

You can do anything, you a director of the movie it does not matter how you achieve the result what matter is what player see at the end.