Outside the United States, the $100 note is the most widely circulated and most often counterfeited denomination. The blue 3-D Security Ribbon on the front of the new hundred dollar bill contains images of bells and 100s that move and change from one to the other as you tilt the note. The Bell in the Inkwell on the front of the note is another new security feature. The bell changes color from copper to green when the note is tilted, an effect that makes it seem to appear and disappear within the copper inkwell.
More info, images and a video showing the new note after the jump.