Update: Zefrank's Earth Sandwich map no longer works. You can now use the Antipode Map instead.
If the earth were a sandwich....
"..If you put a piece of bread on the ground, and somebody exactly opposite you (on the other side of the world) put a piece of bread on the ground, you would have an Earth sandwich!"Try it out:
It turns out that Waipatiki, New Zealand and Madrid, Spain have an interesting connection with one another! :) Give it a try to see where you end up. The geo developer has placed some other good country-combos along the bottom of the map for you to check out. This tool makes it very easy to move the map around and see your "sandwich partner" as you center the map. Good fun!