David Kestenbaum

Planet Money has obtained a secret government report outlining what once looked like a potential crisis: The possibility that the U.S. government might pay off its entire debt.

It sounds ridiculous today. But not so long ago, the prospect of a debt-free U.S. was seen as a real possibility with the potential to upset the global financial system.

We recently obtained the report through a Freedom of Information Act Request. You can read the whole thing here. (It's a PDF.)

Last year, as part of a reporting project, we bought a toxic asset — one of those complicated financial instruments that that nearly brought down the global economy.

We spent $1000 of our own money and bought a tiny slice of a bond backed by mortgages. We paid just a fraction of what it originally cost. It was such a good deal, we thought maybe we'd make a few bucks, which we'd give to charity.

The U.S. has the dollar. Japan has the yen. Now some people are trying to invent a new currency that's not tied to any country or government. It's called bitcoin.

Bitcoin is a lot like cash — for the online universe. It doesn't actually exist in the physical world. You can't hold bitcoins in your hand because they just live on computers and the Internet.

You would never look at a map of the Hudson River, point to the spot where the Tappan Zee Bridge is, and say, "Put the bridge here!"