The 1856 British Guiana One-Cent Magenta isn’t much to look at, with its octagonal corners and faded red paper bearing the faint outline of a three-masted ship. Over the years, however, the stamp some say is the rarest in the world has been sought after by wealthy collectors, and is now featured in an exhibit at the National Postal Museum in Washington, D.C. Over at Smithsonian.com, writer Alex Palmer explains what makes the tiny piece of paper so special—and why it recently sold for a staggering $9.5 million.

In 1855, Great Britain was supposed to ship 50,000 stamps to the fledgling South American colony of British Guiana. But a mix-up occurred, and only 5,000 arrived. How could mail move without postage? The local postmaster came up with a makeshift solution: He turned to the local newspaper, the Royal Gazette, which printed a provisional stamp to tide people over until more stamps arrived.

The newspaper tried to make the new stamps—one-cent for newspapers, four-cents for letters—look as much like official government-issued postage as possible. They inscribed them with a barque—a sailing ship that was common in the 19th century—and the colony’s own Latin motto, which translates to “We give and we ask in return.”

More postage eventually arrived in British Guiana, and it’s thought that the hastily made stamps were discontinued from circulation after less than three months. Since people generally save letters but dispose of newspapers, the one-cent stamp all but disappeared.

That changed, however, in 1874, after a 12-year-old stamp enthusiast named Vernon Vaughan found a well-worn, postmarked one-cent stamp among his uncle’s papers. The boy sold it for the equivalent of $10 in today's money and used the proceeds to purchase a set of flashier foreign stamps.

The One-Cent Magenta passed among private owners until one of history’s most prolific stamp collectors, Count Philippe la Renotiere Von Ferrary, purchased it at a private sale in 1878. After Von Ferrary died in 1917, his collection was donated to Berlin’s postal museum.

When World War I ended, France seized the stamp collection. It circulated among well-heeled owners until John E. du Pont purchased the One-Cent Magenta at auction in 1980 for $935,000.

Du Pont’s own life was as dramatic as the stamp’s, if not more so. The wealthy chemical company heir, philatelist, and wrestling fan murdered Olympic gold medal winner Dave Schultz in 1996 and was imprisoned until his death in 2010. After du Pont passed away, the One-Cent Magenta went up for auction and was bought by shoe designer Stuart Weitzman for $9.5 million in June 2014. As Smithsonian.com points out, “that’s four times more than any other single stamp has ever fetched.”

Thanks to the stamp’s colorful and curious history, curators at the Postal Museum have long been eager to showcase the One-Cent Magenta in an exhibition. However, they were always turned down—that is, until Sotheby’s asked the Smithsonian if they could authenticate the stamp using some of their cutting-edge scientific equipment. To return the favor, the auction house touched base with Weitzman to see if he’d be interested in loaning the One-Cent Magenta to the Smithsonian. Weitzman agreed, and the rarely-seen stamp finally went on display in June 2015.

For now, it looks like the stamp's far-flung travels have come to a close. Philatelists, and the generally curious, have until November 2017 to see the pricey historical relic for themselves.

[h/t Smithsonian]