10 Dollars - Elizabeth II Inverted Jenny

The Inverted Jenny — the 1918 U.S. airmail stamp on which the Curtiss JN-4 biplane was printed upside down — remains the most famous printing error in American philatelic history. The entire known supply of 100 error stamps was purchased by a single collector at a Washington, D.C. post office, and the block of four sold at auction in 2005 for $2.7 million. Solomon Islands has issued this coin under a licensing arrangement that embeds a genuine fragment of an Inverted Jenny stamp within the piece — the 45 mm diameter accommodates the insert rather than reflecting any conventional bullion specification.