A close-up of the front of the US 10-dol

A close-up of the front of the US 10-dollar bill bearing the portrait of Alexander Hamilton, America's first Treasury Secretary, is seen on December 7, 2010 in Washington, DC. Various security features are imprinted into the bank note. Different denomination security threads have various colors which are visible when lit by ultra-violet light. The security features found in United States currency are selected after extensive testing and evaluation of hundreds of bank note security devices, many of which are used successfully by other countries with lower production and circulation demands. AFP PHOTO / Paul J. RICHARDS (Photo credit should read PAUL J. RICHARDS/AFP via Getty Images)