25 Dollars - Charles III Hawaii

Hawaii was never under British rule, but Charles III's connection to the islands is purely philatelic — this coin honors the 1851 Hawaiian Missionary stamps, among the rarest and most valuable stamps in existence, several of which have sold at auction for over a million dollars. The "Missionaries" were printed on thin tissue paper intended for dispatches home, and fewer than fifteen examples of the two-cent value are known to survive.