For much of history, the Middle East has been the capital of concentrated wealth. Whether it is oil, gold or empires, the cradle of civilization has always been a place of opulence.
It all started early, with the Persian empire under Cyrus the Great. In the armory and treasury at Persepolis was a hefty 120,000 talents of bullion. That made the stash a sizable 115 million oz in total. The Umayyad Caliphate continued the trend by building the biggest empire at the time, which spanned from Spain and Morocco all the way to modern day Pakistan. That's 5.1 million sq. miles.
Today, the Middle East still has concentrated wealth. The WSJ found that Middle East billionaire wealth grew 12.4% in 2013. Perhaps even more impressive: for every ten barrels of oil in world reserves, Middle Eastern countries in OPEC have eight. A country such as Kuwait, which is half the size of Maryland, has the 6th highest reserves in the world and is producing almost 3 million barrels a day.