Looks like the USD is on its second iteration. Originally there were the United States Notes (aka Greenback) which were replaced with Federal Reserve Notes. (T

Looks like the USD is on its second iteration. Originally there were the United States Notes (aka Greenback) which were replaced with Federal Reserve Notes. (The Birth of U.S. Fiat Currency - http://www.bloomberg.com/news/2012-04-02/the-birth-of-u-s-fiat-currency.html http://www.bloomberg.com/news/2012-04-02/the-birth-of-u-s-fi...)