Planet Money at NPR:
"For thousands of years, people used gold as money. But why gold? Why not some other element? We tracked down an expert to find out."
Here's more on why gold beat Lithium, Osmium, Einsteinium...
While we are at it, what is GDP:
. The European bailout, explained
. The economic history of the world in four astounding minutes
. Oh wow. Keynes vs. Hayek, on video