A rare US postage stamp has sold for $2m (£1.63m) in a New York auction, setting the record for the most expensive single US stamp sold.
The famous red, white and blue "Inverted Jenny" stamp dates back to 1918 and originally cost 24 cents.
Its fame is tied to both its rarity - only 100 were printed at the time - and also because the plane it depicts is printed in error upside down.
It was purchased by stamp collector Charles Hack.
Mr Hack made the monumental purchase on Wednesday as part of an auction by Robert A Siegel Auction Galleries, based in New York City.
The 76-year-old told the Washington Post that he had been eyeing the coveted stamp since he was a child, calling it the "holy grail of postage".
The Inverted Jenny stamp was part of a collection made to mark the start of regular airmail service.
It features an image of the Curtiss JN-4 airplane in the center, though it is printed upside down in error. Only 100 of those inverted stamps were sold to the public, and they have since become highly coveted by stamp collectors globally.
The stamp is so well-known that it once featured in a 1993 episode of the long-running American animated sitcom The Simpsons.
In it, Homer Simpson is seen looking at a sheet of Inverted Jennys while at a yard sale.
"The airplane's upside down," he says, before throwing the sheet away in a pile of other priceless American artefacts, including a copy of the Declaration of Independence.
The stamp's value skyrocketed almost instantly after it was originally printed thanks to its rarity, and copies of it have sold at several auctions in recent decades.
Mr Hack himself is the owner of a few other Jennys, he told the Washington Post. He bought one in the early 2000s for about $300,000 (£244,329).
In 2007, he bought another, better-quality stamp for nearly $1m. It was the 57th stamp printed in the original sheet of 100.
The one most recently sold is number 49, which has long eluded aficionados of the Inverted Jenny as it had not been seen for a century since its original purchase in 1918.
It had been held continuously in a bank vault by its owner and his descendants, before it was sold in 2018.
It is regarded as "one of the finest centred examples" of the Inverted Jenny, according to Siegel Auction Galleries, as it has rarely been exposed to light.
"The gum is Mint Never Hinged and, since its exposure to light has been limited, the stamp's colours are rich and the paper is bright," Siegel Auction Galleries wrote in the stamp's description.
Mr Hack told the Washington Post that he intends to continue the century-long tradition of protecting the stamp from light and preserving it, calling it a piece of "American history."