It's real money, but it doesn't exist.

If you stacked every bill the Federal Reserve System destroys each year, it would reach 463 miles.  That's one of the facts listed on the glass behind me.  Another interesting fact:  3 out of the 4 cities on my tour schedule this summer have Federal Reserve banks in them.  My cameraman is thrilled at the prospect of visiting 2 more Bank/Museums.

In related news, here is an amusing "Proof" of where money comes from, submitted by G.R., who claims the source is anonymous:

Postulate 1: Knowledge is Power.
Postulate 2: Time is Money.

As every engineer knows,

Work
---------- = Power
Time

Since Knowledge = Power, and Time =Money, we have

Work
--------- = Knowledge
Money

Solving for Money, we get:

Work
----------- = Money
Knowledge

Thus, as Knowledge approaches zero, Money approaches infinity regardless of the Work done.
Conclusion: The Less you Know, the more money you Make.