Prime Meridian.
It's 12:00 now where you live right (sorry i didn't see this)
Anyways
Longitude runs vertically on a globe, and latitude runs horizontally. The equator is the center, zero degrees latitude.
The tropic of capricorn and cancer are both latitude lines, showing how far down the sun shines directly.
Prime meridian is 0 degrees longitude. (i think.) So it would have to be the prime meridian.