An exceptional 24c Inverted Jenny stamp is the star lot of Robert A Siegel's auction of the Curtis Collection of US 20th Century and Air Post.

The sale of the $450,000-estimated stamp takes place in New York on February 23-24.

The Inverted Jenny is the world's best known error stamp

Collector William T Robey discovered a single sheet of the errors in a Washington, DC post office in 1918. He later sold them on to fellow collector and noted eccentric Colonel HR Green for the princely sum of $20,000.

Green then split the majority into singles for sale.  

Siegel comments: "Many of the original 100 stamps were mistreated by collectors during the years, despite the stamps' rarity and value.

"Colonel Green himself allowed moisture to affect some of the stamps he retained. Other examples have become slightly toned from improper storage and climatic conditions.

"Hinging has caused thins and creases in numerous stamps, and at least seven have been "lost" to philately - or nearly so as in the case of the copy swept up in a vacuum cleaner. The stamp offered here is well-centered and remarkably fresh."

Collector and investor Bill Gross bought a block of four Inverted Jenny stamps for $2.9m in 2005. 

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