Well heres my opinion:
It all comes down to what you believe in; If there is a "beginning" to the universe, then I believe that you would reach a point in space where literally nothing exist, no time no space and no mass, because scientifically, the universe is contracting, so there must be an end, so, when you reach that point and (try) cross the border, you would:
a. Disintegrate at the border
b. Never make it there, and just fell a wall (
), because humans are composed of enrgy/matter and to pass matter through nothing, is like walking into an impenetrable wall.
Now, if you dont believe in "The Big Bang", then I don't think that space will ever end, because it must be infinite if it doesn't have a beginning. And in that case...perhaps God might solve the puzzle?
If you don't understand one bit of this post, then don't worry, i'm pretty confused right now my self
.