The North Pole. The furthest point North one can travel. No problem so far.
But what time is it there? If all time zones intersect at this one point and the International date line also terminates here, when is it? The official answer - because we don't like uncertainty - is here. At latitude 90 °, both at the Northern and Southern pole the time is GMT or UT -universal time, the same time as London and along the prime meridian. Fair enough.
Yet who made this arbitrary decision for the when of the poles? Was there a vote? A panel of chronologists? After all, nobody owns it, although Canada claims it, it's over 450 statute miles from any land and hence in international waters. What happens - in a temporal sense - when you walk around the poles? How far south does the annex of time extend? Even though geometrically the pole is a point and as such has zero dimensions, as geographical space it must have a radial area to have meaning.
How far must you travel south* before "time travel" is possible? What is the shortest time one could technically complete a 24hr day by: Walking? Running? or even Speedboat**? Would the journey's circumference need to be greater than an Olympic Stadium track?
On a standard Mecator projection map of the world, if UT extends around the pole, the Zulu time zone would appear to reach across the entire top of a map creating a distorted Greenland effect margin? How wide would that margin be? A related question about the assigned temporal properties of a topographic 'point', how deep do you have to go down before you are technically no longer at the North Pole?
At present I have few definitive answers but what research I have done suggests that anywhere falling through the cracks of our flat earth maps and minds, gets UT time slapped on it, hence London loans out its noon to the moon, the poles, and presumably the center of the earth.
*From the pole randomly start walking in a straight line.
**A recent trend in the Summers of the Early 21st Century.