Potholes in Space-Time

[HerbertSu]

I know this may fall under the area of speculations but I just wanted to put this in relativity since it kinda has stuff to do with time.

 

People say time travel (too the past at least) can never be achieved because it would mess up space time or because the universe will never let it, but what if we made distinct moments or places in time that allowed a person from the future to visit that moment without affecting anything. Would that work in allowing people from the future to visit their past (or our present).