All the gold mined in the world would cover a football field to a depth of 5.25 feet, according to a fascinating one page summary in the new issue of Fortune magazine. At a price of $1,483 per ounce (as of 5/17/11), the 166,600 tons of gold that has been mined is worth $7.9 trillion. They say the U.S. government reserves are 4.9% of the world total, worth about $386 billion. [photo credit, Smithsonian Institution]