In 1918, collector William Robey purchased a sheet of 100 stamps from the main Washington post office for $24.
He afterwards noticed that the plane shown on the stamps was upside down. One week later, he sold the sheet for $15,000.
More than 90 of those stamps still exist, but there is only one plate book.
That one was sold on Wednesday for $2,970,000 to an unrevealed private collector.
In June this year, another "Jenny" stamp, this time a single one had been sold for $525,000.
And sixteen years ago, in 1989, the plate sold on Wednesday had been auctioned for $1, 1 million.
Scott Trepel, president and owner of Robert A. Siegel Auction Galleries, wouldn't want to reveal the identity of the buyer. Not now nor back in 1989.
Trepel declared: "I'm going to respect his desire for anonymity. I think he got his thrill owning the plate block and wouldn't get much of a thrill at having the world know his name."
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