Antipodes: Middle of the Indian Ocean,
Through to the same latitude on the other side: "Singyang" province, China.
Don't forget that with respect to digging through to the antipodes, once you get to the earth's center, the remaining digging will all be upward.
Nertz to that sez me.
(Incidentally, a corollary of that is there is no gravity at the center of the earth. Or any other body, for that matter. I've been toying with the idea that this is also true for black holes, zero gravity at their centers; don't know if anyone else has dealt with that issue.)
Terry, 230RN