Anyone who enjoys a little a bit of antiquing, dreams of finding a genuine treasure hidden somewhere amidst the dusty knickknacks, rickety furniture, and other bric-a-brac that tends to fill most second-hand stores. It is certainly the case that some people are lucky enough to track down a real gem amidst the jumble—but few stories are as remarkable as the painting that was discovered at a Pennsylvania flea market in 1989.

The painting, a simple, somewhat dreary-looking landscape picture of some countryside by an artist whose signature was unreadable, was bought at a store in Adamstown by an anonymous buyer, who admitted he was more interested in its pretty gilt frame than the image inside it. He paid just $4 for it.

Some months later, when the time finally came to remove the painting from its frame so that it could be used elsewhere, the frame sadly splintered apart; but as it did so, a small folded document dropped out onto the floor, from between the canvas and the frame’s wooden backboard. On closer inspection, the document turned out to be an original copy of the Declaration of Independence.

After the Declaration of Independence was signed on July 4, 1776, a local printer in Philadelphia named John Dunlap was hired to reproduce dozens more copies of the document. The plan was that these copies—which perhaps numbered as many as 200—could then be distributed to government and military leaders, and various towns and cities, right across the original 13 colonies, bringing news that America was now an independent nation.

The copy found behind the $4 painting was just the 24th of these original 1776 copies known to exist at the time. Unsure of just how remarkable a discovery it was, in 1991 the owner took it to Sotheby’s auction house to have it appraised; it was valued at anywhere between $800,000 and $1 million. “Here was the most important single printed page in the world, in the most spectacularly beautiful condition,” auctioneer David Redden, the vice president of Sotheby’s, told the LA Times at the time. “The fact that it has been in the backing of the frame preserved it,” he went on, describing the document; which evidence showed was folded while the ink was still wet, way back in 1776, as “unspeakably fresh.”

The copy of the Declaration went up for sale at Sotheby’s on June 4, 1991, and defied all expectations to sell for a staggering $2.42 million. Not a bad return on a $4 investment!