Now let's return to the main subject: Parallel Universes exist in the same place in the same time but not necessarily mean in the same universe...In layman's terms: You don't occupy the same space as your parallel version's....

There are also somethings that are more complex than the above situation.Such as in the name "parallel", These dimensions would never meet. In one universe,Adolf Hitler may have won the Second World War and all of Europe would have the banner of Nazi Germany.Bill Gates might not have founded Microsoft. or what's worse is that We would have discovered the internet.In each second the generation of multiple parallel universes might occur.

Maybe in the future, We may be able to see the universes parallel to ours'. Who knows...We may already have discovered the technology and used it for commercial purposes.Well only time or shall I say. In another universe shall the story be told.
Sources:Wikipedia - Multiverse