"You could take all the gold that's ever been mined, and it would fill a cube 67 feet in each direction. For what that's worth at current gold prices, you could buy all -- not some -- all of the farmland in the United States. Plus, you could buy 10 Exxon Mobils, plus have $1 trillion of walking-around money. Or you could have a big cube of metal. Which would you take? Which is going to produce more value?"