(distance) What is the end of the universe?

i have 2 thoughts on this question. First is that its just like a pacman game. when you reach a certain point you will go back to the beginning. my other thought is that our universe is inside of another and it continues on forever. or say we look at an atom an go to the smallest thing which most people knows is an electon. say scientifically there is something smaller which i know there is but dont know the name of it, well inside of the smallest known or unknown thing, that is our universe. and inside that atom or smallest thing is another universe. it will just continue.