The Big Bang - a pretty difficult concept to get your head round, right?
How could there be absolutely nothing before it? How could everything come from one point? How can something expand a billion miles in just one second?!!
Well fret no longer for the lovely people at Kurzgesagt have created this video which eloquently explains the origins of our universe.
Of course there are still un answered questions - "Is this the first and only universe? Were there universes before our own?"
But even the super-boffins don't know that yet but you can bet when they do, Kurzgesagt will produce a video to explain it.