Global military spending

Rank		Country	Spending ($ b.)	World Share (%)
—		World Total	1339	100
1		United States	547	45
2		United Kingdom	59.7	5
3		China	58.3	5
4		France	53.6	4
5		Japan	43.6	4
6		Germany	36.9	3
7		Russia	35.4	3
8		Saudi Arabia	33.8	3
9		Italy	33.1	3
10		India	24.2	2
11		South Korea	22.6	2
12		Brazil	15.3	1
13		Canada	15.2	1
14		Australia	15.1	1
15		Spain	14.6	1

Early development of different continents

What is the reason that Europe and Asia evolved faster than the rest of the world? The same natural resources exist all over the world.  So, Why Eurasia and not the Americas, or Africa? There are four theories:

Animals: The availability of domesticated animals allowed farming, transportation, and surplus food. This allowed people to find other things to do other that look for food all day. Horses, Camels, Sheep, Pigs, Chickens and Cattle all came from Eurasia. Native Americans never domesticated the Buffalo or Antelope. South America domesticated the Lama and Alpaca which provided pack animals which allowed the Inca and Maya to form advanced civilizations. Africa never domesticated the Zebra, Hippo, or Elephant (only the Asian elephant can be trained.)

Horizontal Axis: The other continents are tall and thin, Eurasia exits on a horizontal axis that provides 4 seasons. Animals migrated from one end of the super continent to the other which gave people longer hunting seasons. The cold winters in the Northern Hemisphere made them plan ahead with planting, harvest, storage, shelter etc.

Iron: When Spain engaged the Aztecs, they were fighting with wood and stone weapons. They had not yet developed sails for ocean vessels or wheels to provide transportation. While Iron was plentiful, they had not yet learned create a fire hot enough to make steel. The Aztecs had bronze and gold, but they used it for decoration rather than weapons. A few hundred Spanish Calvary soldiers with guns and steel swords conquered several million Aztecs. It seems unthinkable, but imagine a few hundred American special forces troops going back in time two thousand years. They could have taken over the Roman Empire. What would medieval knights have done against a stealth bomber? That was the difference of technology of the Aztecs and the Spanish.

Staples: Europe had wheat and barley, Asia had rice, North America had corn, South America had potatoes. These are all pretty similar in calories and abundance. Sub Saharan Africa lacks a solid native staple food product. They do not have a clear planting season. The warm summer rains and long, hot days are not conducive to farming, so the feast/famine cycle has existed to this day in Africa.