What Gives a Dollar Bill Its Value?

Next week we'll see us all in Berlin again... and it's most likely that we'll spend a lot more of our hard earned cash than we originally intended to do. So this animation below might not only be a highly entertaining but a useful one.
“The value of money is determined by how much (or how little) of it is in circulation. But who makes that decision, and how does their choice affect the economy at large? Doug Levinson takes a trip into the United States Federal Reserve, examining how the people who work there aim to balance the value of the dollar to prevent inflation or deflation.“ (Forty)