The Mystery of Consciousness: Origin, Nature & Theories of Subjective Experience & Self Awareness

What is consciousness? How does it originate? Why does it seem to be a trait primarily found in some living organisms with relatively complex brains? How does the brain generate the feeling of existence? Why each of us has our own inner universe? How does the functioning of the 86 billion brain cells create this seemingly meta-physical realm of thoughts and emotions? Does it all come from some precise arrangements of cell connections in the brain?

Is there an aspect of consciousness that can’t be explained by physical facts alone?
Is it an intrinsic aspect of nature that exists beyond the physical laws?
Being human and having subjective experiences is a truly remarkable and privileged experience, but what if this extraordinary experience expands beyond biological entities? Could there be also an experience comparable to being a star or a planet?

Where does consciousness originate? When it begins? Why does it exist within us? Why does it exist at all?