The story goes that The Lakota holy man Black Elk took poet John Neihardt to the top of Harney Peak in the Black Hills to pray, explaining that it was the center of the world. When Neihardt asked how he knew that, Black Elk chuckled at the white man's innocence and with patiently explained that on a ball like the earth, every place is the center.
That said, two spots on the earth command special attention: the North and South Poles, where a hypothetical axis would pass through the surface. Of these two, we give the north pole particular importance. This makes sense, since civilization mostly arose on four great rivers of the world: Nile, Hwang-Ho ("Yellow"), Indus and Tigris-Euphrates, which are all in the northern hemisphere.
Suppose, instead: five or ten thousand years ago, a group of southern hemispherites decided to quit all that tedious huntin' and gatherin' and settled down by the banks of the Plata or Orange rivers, say, in South America and South Africa respectively; their settlements multiplied in size and sophistication; almost before you knew it, they invented maps and sundials and compasses, long before anyone in the other hemisphere on the far side of the equator had given such things a thought. How would our world today be different if that's the way it had happened? Probably:
1) South would be at the top of maps (see illustration).
2) The direction "clockwise" would be opposite from how we define it now, since the hands of a clock model the shadow of sundials. In the southern hemisphere, shadows go the other way.
3) The names of the zodiacal constellations would be different. Viewed from, say, Australia, Orion the Hunter is standing on his head while Leo the Lion lies on his back with his paws in the air -- hardly heroic or imposing poses.
4) The art of navigation might not have arisen as fast as it did, since there's no equivalent bright star in southern skies to Polaris, the North Star. And even if early navigators had figured out celestial navigation, they might have had more trouble crossing oceans, since there's a lot more ocean in the southern hemisphere than in the north. For instance, it's about half as far again from Cape Town to the mouth of the Plate as Columbus' route across the Atlantic from the Canaries to the West Indies.
You can take this speculation to extremes. Would faucets turn in the opposite direction? Rotary phones? Would Republicans veer to the left?
Barry Evans (firstname.lastname@example.org) worries which way the water in his bathtub will go when he pulls the plug in Old Town Eureka, where he lives.