This is an excellent question with many opinions and which generates more questions the more we learn about our Cosmos. One thing we can say is that the Universe evolved from a really small point in the void. A point with no dimensions, no volume and filled with an infinite amount of energy! Why do I use the word “void”? The answer is that before the Universe existed there was NO space. The Big Bang created all the space and matter at that instant in time. There are many theories such as the “brane” theory that speculates that our Universe leaped into existence when two branes in a multiverse filled with an infinite number of “other” Universes overlapped and brought about the creation of our Universe. Most of these theories tend to be more science fiction than science fact. One interesting fact is that at the instant of the Big Bang a nearly equal amount of matter and antimatter was created. For every billion particles of antimatter produced a billion and ONE particle of matter was produced. We all know that when antimatter and matter touch their entire mass is turned into energy. As a result of this slightly asymmetric amount of matter that was produced the Universe came into and stayed in existence. Had the Big Bang been perfectly symmetrical everything would have been annihilated and nothing would exist. Everything we observe in our Universe is only one billionth of what was originally created at that very special moment in time we all call the Big Bang.In the long run no one really knows where the Universe came from. The only thing we do know is that our Universe is a very special and unique place!