The rules change depending on the universe in question. However, here is this ones theorized breaking point:
You will have to build a large gravity manipulating machine. Crash the waves in on each other in overlapping crashes.
Bare in mind this machine must be built to scale and to open a roughly door sized hole will require a near solar system to galaxy sized machine for perhaps only a brief time, in exchange for a galactic ton of resources.
Now a hole will crack in reality, most of them are empty space, but fine tuning the depth of this void will eventually lead you to parallel -verses- and beyond. The ideal being that it doesn't randomly find a dimension made of dark matter and incinerate us all in the attempt, and rather leads to a universe filled with oil or a universe with free electricity instead, but also it has a small percentage chance of being blocked by "something else", I'll leave that "thing" to imagination.