Do you believe in Parallel Universe?

There is a concept that suggests that there could be other universes besides our own, where all the choices you made in this life played out in alternate realities. The concept is known as a "parallel universe," and is a facet of the astronomical theory of the multiverse.

Around 13.7 billion years ago, simply speaking, everything we know of in the cosmos was an infinitesimal singularity. Then, according to the Big Bang theory, some unknown trigger caused it to expand and inflate in three-dimensional space. As the immense energy of this initial expansion cooled, the light began to shine through. Eventually, the small particles began to form into the larger pieces of matter we know today, such as galaxies, stars, and planets.

One big question with this theory is: are we the only universe out there? With our current technology, we are limited to observations within this universe because the universe is curved and we are inside the fishbowl, unable to see the outside of it (if there is an outside.) 
Source: Space.com

You must have seen such a concept in Tv series as well such as The Flash, The Man in the High Castle, etc.

What are your views on it?  What would it be like if we come across such thing in real life one day? What would you want to be in the parallel universe?