The $1 dollar bill is one of the most touched objects in our world, changing millions of hands throughout its life span. Yet, how often have you actually stopped to look at one? Carefully study it? Probably never. And, of course, that every single letter, number or symbol on the dollar bill was put there for a reason. In this slideshow, we give you the explanations behind 11 such markings: little-known facts about one of the most used currency notes.