Currency

Currency is interesting. Its all in what you value I suppose. Early Ethiopian Kings scoffed at the gold and grown food they were offered by the Kings of Persia, saying the gold was flimsy and that his people would never eat anything grown with cow dung (fertilizer). Early North American Natives used shells as a medium of exchange, and these moved from Central America up through the southern Atlantic region (Virginia). Its all what you value.

Some 25,000 years ago our ancestors put far more value on flint than anything else. There settlements patterns seem to be built around where they got flint. They used this to make tools for hunting and agriculture. So much for peaceful, hippie like folks living in the wild.

Man's first currency. Material to make weapons. Thus began the military industrial complex.

Read on!  Though be advised, I carried their conclusion out a bit. :)