What was the Universe before the Big Bang happened?
Before the beginning of the universe with the big bang there was no space, no time. There may have been mass and energy. It is not clear where this mass and energy could have come from or if matter and energy existed before the creation of the universe.
It is clear from the empirical evidence that the universe had a beginning. This beginning is called the big band. It is also now clear from empirical evidence that the universe will have an ending.
The evidence from the supernova studies of 1997 and 1998 indicate that the rate of expansion of the universe is increasing. This means that the universe will not recycle instead it will end in a heat death.
Since the universe had a beginning and will have an ending it is clear that matter and energy can not be eternal or self existent. If matter is not self existent then where matter and energy came from is an open question because the universe is therefore an open system.
The Universe did not exist before the big bang and the beginning of the universe: no space, no time, no self existent matter and energy.