Here's a big denomination note the public was never meant to see! That's because it was intended for interbank transactions only. Issued between 1929-45, these scarce notes feature a portrait of William McKinley on the face with an engraved back design. Over 60 years ago in June 1945, 74% of all $500 FRNs had been redeemed and destroyed. With green Treasury seal and serial numbers, plus Julian-Morganthau signatures.