Six or so miles off the southeast coast of England, in the cold, gray waters of the North Sea between the Netherlands and Great Britain, sits a nation.

"Nation" might be overstating things. It's a stretch, for many, to consider a small, mostly abandoned, rundown and rusting World War II fort on a massive pair of concrete stilts in the middle of the sea a nation. But there it sits, unmistakably, with a ruling family, a flag, a slogan, an anthem and a name straight out of a cheap novel.

All hail the sovereign Principality of Sealand!

A mighty micronation

Every once in a while, some shaker-upper tries to launch an independent nation. They’re dubbed "micronations." A Las Vegas millionaire built up some reef in the South Pacific as the Republic of Minerva in the early 1970s before Tonga took it back. Some New Yorkers tried to start a nation on a ferro-cement boat and moor it near the Bahamas in the 1970s in something called Operation Atlantis. They were chased away, and their boat eventually sank.

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Sealand, though, is a micronation with staying power. Despite the fact that no one lives in the former fort year-round — not the founder when he was alive, not the founder's family, no one — despite struggles to keep it financially solvent, despite regular challenges to its very being, Sealand is approaching is 50th anniversary.

Paddy Roy Bates and his wife Joan founded Sealand in 1967. Evening Standard/Hulton Archive/Getty Images

In 1966, founder Paddy Roy Bates, a former British infantry major, was looking for a place to base his pirate radio operations, after getting kicked out of another sea-based fort off the coast of England. Bates, trying to avoid the long arm of British law, settled on another of the Maunsell Forts, this one named Fort Roughs, which was in international waters at the time.

A few months later in 1967, the self-appointed Prince Roy, along with his wife Princess Joan and their children Michael and Penelope, raised the Sealand flag.

The Bates family — notably Prince Michael, who took over as the de facto head of state after Roy's death in 2012 — has been in charge ever since, warding off periodic legal challenges to the nation's legitimacy and an armed invasion in 1978.

"It's a massive part of our lives," Prince James, Michael’s son, told the Echo newspapers in Essex, England, earlier this year. "Houses have been remortgaged and jewelry sold over the years, but it's finally got to a point where it's paying for itself."

Keeping Sealand afloat

The coat of arms of Sealand. Wikimedia Commons

Sealand pays its bills now mostly through donations and its online shop, where you can buy things as varied as a T-shirt with the nation's motto — E Mare Libertas ("From the Sea, Freedom"), as seen on the coat of arms of Sealand to the right — to official titles. You can, for example, become a lord, lady, baron or baroness of Sealand, or a count or countess. For about $157, you can become a Knight (or Dame) of the Sovereign Military Order of Sealand. (Included with your title: An "Elegant Official Documents Folder.")

Knights and dames, supposedly, protect Sealand from invasion, like the one in 1978. A German businessman and his gun-toting team invaded Sealand that year while Prince Roy was away, taking Michael hostage. In a bit of James Bonds-esque turnabout, Roy returned, rappelling down to the platforms while his helicopter was taking fire — the helicopter pilot, in fact, was a stunt pilot in James Bonds films — and joining Michael and other Sealanders in turning the tables on the Germans.

Prince Roy let all of the invaders go but one. It took a German diplomat some seven weeks to negotiate the hostage's release, which Prince Roy used as another validation of Sealand's independence and legitimacy.

Sealand has good and bad years, economically speaking, but the royal family has kept it afloat. Ryan Lackey/flickr

Over the decades, Sealand has had good years and bad years, and has tried many avenues to boost its finances. The nation issued passports to all comers for years, but suspended that after many were used illegally. Sealand officials allowed a Red Bull video to be shot there a few years ago. It has, on at least a couple of occasions, been a host for web servers. Many of the country's efforts have failed. "It would probably be more economical for you to spend your money on a three-legged race horse," Prince Michael said of his country's economic woes during a Reddit AMA in 2013.

Still, almost 50 years after self-proclamation, the Principality of Sealand remains — proudly, and perhaps a little unlikely, considering it still is not officially recognized by other nations — afloat.

"Sealand is a on-off that could never be repeated in international law due to a unique set of circumstance," Prince Michael told the Guardian in 2012. "There's nowhere else where you could do what we did. I think you'll find everything is claimed now."