United States 20 Dollar Bill

The United States twenty-dollar bill ($20) is a denomination of United States currency. U.S. President Andrew Jackson is currently featured on the front side of the bill, which is why the twenty-dollar bill is often called a "Jackson," while the White House is featured on the reverse side.
The twenty-dollar bill in the past was referred to as a "double-sawbuck" because it is twice the value of a ten-dollar bill, which was nicknamed a "sawbuck" due to the resemblance the Roman numeral for ten (X) bears to the legs of a sawbuck, although this usage had largely fallen out of favour by the 1980s.The twenty dollar gold coin was known as a "double eagle". Rather than a nickname, this nomenclature was specified by an act of Congress.
The Bureau of Engraving and Printing says the "average circulation life" of a $20 bill is 25 months (2 years) before it is replaced due to wear. Approximately 22% of all notes printed today are $20 bills. Twenty-dollar bills are delivered by Federal Reserve Banks in violet straps.

external image 300px-20dollarbill.jpg
external image magnify-clip.pngObverse of the Series 2004 $20 bill
external image 300px-Us_twenty_dollar_new_back.jpgexternal image magnify-clip.pngReverse of the Series 2004 $20 billexternal image 180px-US_%2420_1905_Gold_Certificate.jpgexternal image magnify-clip.pngSeries 1905 $20 bill
external image 180px-U.S._%2420_1914_Federal_Reserve_Note_RS.jpgexternal image magnify-clip.pngSeries 1914 $20 bill

external image 180px-US_%2420_1929_Federal_Reserve_Bank_Note.jpgexternal image magnify-clip.pngSeries 1929 $20 bill

external image 180px-US_%2420_1985_Note_Front.jpgexternal image magnify-clip.pngSeries 1985 $20 Note

external image 180px-US-Series-1995-%2420-Obverse.jpgexternal image magnify-clip.pngSeries 1995 $20 bill

external image 180px-US_%2420_under_blacklight.jpgexternal image magnify-clip.pngThe security strip in a twenty-dollar bill glows green under a blacklight.