We mentioned in the first article the widely-held misconception so many people have that by digging straight down from the United States we could eventually reach China. But what really does lie straight down under our feet? What part of the Earth is really directly opposite our location? This point is called our antipode; it derives from both Latin and Greek and basically means "opposite the feet." If you're at the North Pole, your antipode is the South Pole, but in other instances it's not so obvious. How can you determine the antipode for any location? Very simply: First, its latitude is always numerically exactly the same as yours bit in the opposite hemisphere, (except if you're on the Equator but exactly 180 in longitude opposite). No matter where on Earth you are, the longitude of your antipode is 180 opposite yours.
Suppose we wish to locate the antipode for Denver, Colorado. Rather conveniently, this city is located quite close the the 40 north latitude parallel as well as the 105 west longitude meridian. So its antipode falls close to the 40 south latitude circle and the meridian that is 180 away; to find it, subtract 105 from 180 and the 75 difference in the direction east of Greenwich, which is 75 east longitude is Denver's antipode. In other words, take your longitude, subtract it from 180, and then go the subtracted difference from the Greenwich meridian in the opposite direction from which your longitude is measured from that prime meridian; if you're west of Greenwich, bo east. Having done this for Denver, we see that its antipode is in the Indian Ocean right by the intersection of the circles for 40 south latitude and 75 east longitude, which happens to be northeast of an island called Kerguelen and quite far from China!
Interestingly, in the days when the British Empire was at its height (and Britannia ruled the waves), its farthest outpost from England was near England's antipode - New Zealand. It's about as far as they could get from the mother country, and in the days before airplanes it was quite a lengthy sea voyage both in time and distance to reach this British Empire outpost. Check it our on your globe, both by the rules we just gave you, and by looking straight through the globe from England (labeled United Kingdom on your globe). What is also rather interesting is that despite its being the farthest location in the Old British Empire, New Zealand still retains a remarkably distinctive British atmosphere.