Counterfeit money

One way to recognize counterfeit money in Argentina is the following: You have to put the note in the light and check if the face of the hero that appears in the right side of the note, appears also in the left, but in a transparent way, in a way that you can only see if you are looking in the light. If it shows the same face in the left side, the note is good. If it doesn´t show the same face in the left side, the note is false.