So it turns out, audits of Fort Knox resolve in gold of a much higher purity than they should. Furthermore 17,000 tons have had to be re-audited and no one will say why.Here's what happened: President Nixon made a back-room deal with visiting aliens: our gold for their technology. He was clever enough to add a clause that if we could improve on their technology we would be paid back in gold. This is where Area 51 spending mostly goes, and the origin of certain Bell Labs innovations.

As it happens our discovery of advanced lithography constituted the improvement, and the aliens made good on their side of the deal. They got out more advanced computers, and we got the gold. But the government couldn't tell anyone about it, and selling it would have lowered the price of gold and raised too many questions. It was stored in Fort Knox. At this same time an auditor died -- the only man who was party to the difference. Now the treasury department knows it has too much gold, and the purity is too high, and they can't move it out without expanding the number of people who know about the aliens. The 17,000 tons, and an additional 100,000 tons of gold are sitting permanently out of the reach of the government in its own vault.