A few days ago,
opium posted in her journal where the opposite side of the world from our region of the world is...a few years back I did the same thing but was never sure if my mathematical geographical estimates were at all close.
Turns out in the end that I was...the opposite side of the world from Vancouver is located in the Indian Ocean near the Heard and McDonald islands, which are Australian territories located closer to the Antarctic continent than anything else.
I looked at a number of populated regions and sadly, it looks like the other side of the world for these areas is usually a big expanse of ocean somewhere.
If you actually wanted to dig straight through the core of the earth and wind up in China, let's say - you'd have to start in parts of Chile or Argentina. Interesting, non?
Check out
this link for the program,
If the Earth were a Sandwich.
-Tim