As part of an effort to stay one step of counterfeiters, the U.S. Treasury Department has unveiled a high tech makeover of the $100 bill. These photos show the new version of the $100 bill and how it changed through decades till its appearance in 1860. The front of the 1890 version of the $100 bill.
Source: How 100-Dollar Bill Changed in 150 Years (23 pics) – Izismile.com