One of the most discussed topics among physicists, astronomers and cosmologists, is the origin of our universe. A number of theories have been put forward to explain the origin of the universe. Based on the evidence, the theory of Big Bang is widely accepted today. What is the Big Bang? Around 13.8 billion years ago, all the energy and the matter was compressed into a miniscule point. There was nothing else, no space or sky outside it. Everything was contained in that point.  All at once, this point (which could not bear that high density and very high temperature), started expanding at an incredibly fast rate. In  a split-second, it was the size of a grape, an instant later, a km-wide. Within a minute, it was billions of km-wide…and so on. Since then, the universe is not only expanding, it is expanding with faster speed as the time is passing. It's a mind-boggling question that has intrigued the scientists and the commoners alike for centuries is: “What was there before the Big Bang? Was there a universe or many more universes before our own universe? Will there be more universes after this universe? Are there parallel universes or cyclic universes? Was there just one big bang (that we know for this universe) or were there two or more big bangs? What are the theories which attempt to explain the phenomenon of the ‘Universe before the Big Bang’.