What is hidden on the $5 dollar bill?

Could you elaborate on the mystery surrounding the $5 dollar bill? What exactly is it that people are claiming is hidden within its intricate design? Is there any truth to the rumors of secret messages or symbols etched onto the currency? If so, how did these secrets come to be, and what do they signify? Are there any historical or cultural significances attached to these hidden elements? I'm intrigued to learn more about the enigmatic aspects of this widely used form of payment.