The entire visible universe and everything that we can see in every direction with Hubble Space Telescopes and other equipment was once in a region that was smaller than an atom. It started with tiny quantum-mechanic fluctuations but it expanded at a tremendous rate. Those fluctuations were stretched to astronomical sizes and those are the same fluctuations that can be observed in the cosmic microwave background.
So lets see the animation which probably is amongst the best that are made so far about the shape and structure of our Universe