Aviation

The original, 1916 version of the Aviation included crème de violette, a violet-flavored liqueur that tinted the drink a pale sky blue (hence its name, some say). Not much later, the liqueur became nearly impossible to find in the US, and this version of the drink-without any crème de violette-became the standard. (Ironically, at least three new brands of crème de violette have launched within the last decade.) Slideshow: More Great Gin Cocktails