The concept of what was there before the Big Bang is difficult for me to wrap my gray matter around. This is why I like the Big Bounce Theory rather than the Big Bang. For me it gives credence to a Multiverse but who am I to even comment
One part of quantum theory is that there are actually multiple dimensions, some that come together for us (length, width, depth and time) and others that we don't have the ability to perceive. Amidst this theory is another that suggests a planer theory, where you might visually consider a dimension as a flat plate. Now consider several of these randomly placed in space (a vast simplification, but the visual will do for now).
One theory suggests that what we know as our dimension is parallel to another planer dimension, only separated by a small gap. So small that sometimes one leaks into the other (an obvious try to explain ghostly phenomenon and such). The "big-bang" that we postulate could actually be thought of as both of these plates touching very briefly, thereby totally annhialating each other's contents and starting anew.
Therefore the "big bang" was not started at a point in space, but simultaneously along the entire length, depth and height of our plane as both planer dimensions touched one another, kind of like two cymbals being clapped together.
So, does that mean what was there before was destroyed? Does it mean that at anytime time these planes could touch again, and the whole shebang starts over? If so then I better stop delaying, and buy my Typhon now.
You've got it. According to the theory, these big bangs of planes touching could have happened before and could happen again, on a million year + cycle.