Great Countries/Empires Mainly in North?

Why does it seem like most great and powerful countries and empires generally are in the northern hemisphere (or the top of the southern hemisphere)? Now, obviously there are plenty of exceptions like Australia but it seems like most are in the north. Why do you think that is?

With significantly less land available for settlement in the southern hemisphere it's obvious why the north was more settled. In the south you have half of Africa, Most of South America and Australia. In the north you have everything else. Given the fact that mankind also began in the north and had extreme difficulty traveling through the massive deserts of Africa they had no where else to settle but the north.

67.29% of the land on Earth is in the Northern Hemisphere.

and there you go

The aliens that planted the seeds of civilization on Earth landed their flying saucers in the Northern hemisphere.

@foxhound_fox: Well that makes perfect sense. Somehow I never really realized that.

because one of the major ways cultures spread is in how cultures bring their crops and animals with them and those plants and animals are limited to a certain latitude and longitude.

get out of that sweet spot and you have nothing to eat and your culture stops spreading.

The majority of landmass is in the Northern Hemisphere. The Inca Empire did extend into Argentina.