I heard an interesting conspiracy theory recently with the basic idea that there isn't a gold stockpile at "Fort Knox" (anymore or ever). With the level of security so great there and reportedly few people having seen the gold, it's an interesting idea and raises the question:
Is there a substantial stockpile of gold at "Fort Knox" (or the Bullion Depository) at present day?
Edit for relevant claim - Brad Metzler's Decoded on History Channel did a show on this. They were unable to find any evidence that the gold was actually there but had several anecdotes from people who knew people who said there was no actual gold in the vault.