The ten dollar bill is a denomination of United States currency that features a portrait of Alexander Hamilton, the first Secretary of the Treasury. It is primarily green in color and has various security features, including a security thread and a watermark, to prevent counterfeiting. The bill is commonly used for everyday transactions and is widely accepted across the country. In addition to Hamilton's portrait, the back of the ten dollar bill showcases an image of the U.S. Treasury Building. The bill has undergone several design changes over the years, with the most recent redesign occurring in 2013, which introduced new security features and updated the overall look of the currency.