Today the Federal Reserve unveiled the new design for the $100 bills. The new bills include additional security features designed to weed out counterfeit notes.
The new design includes a 3-D security ribbon that contains images of bells and 100s that move and change from one to the other as handlers tilt the note. A new image of the Liberty Bell in the inkwell changes color from copper to green when the bill is tilted.
It also features phrases from the Declaration of Independence and the quill used by the Founding Fathers to sign the document on the right hand side of the front of the bill. On the back, there's a new image of the back of Independence Hall. Both that image and Franklin's portrait have been enlarged, and designers dropped the oval around both images.
The Federal Reserve Board will start issuing the bills Feb. 10, 2011. The older bills will still work and will eventually be cycled out of the market, Bernanke said. [source]