The U.S. State Department "strongly recommends against" travel to North Korea by U.S. citizens, warning that "foreign visitors there may be arrested and detained or expelled for activities that would not be considered criminal outside North Korea."
They're not kidding.
Recent news reports detail the saga of three Americans currently being held in North Korea who have been pleading, so far unsuccessfully, for help getting out. In the past, other tourists have been seized and released a month or more later.
Kenneth Bae, the owner a China-based company specializing in tours of North Korea, and Jeffrey Fowle, a tourist, are accused of "hostile acts" against the state. North Korea news media report that the third detained American, Matthew Miller, allegedly tore up his tourist visa and claimed to be seeking asylum.
Which may leave you wondering: do people really go to North Korea on vacation?
Evidently they do.
"Somewhere over 6,000 Westerners go there each year, mostly coming in via China," said Robert Willoughby, author of the Bradt Guide to North Korea, which is about to be published in its third edition.
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Americans probably make up about a quarter of those Western visitors, said Willoughby, but he said tens of thousands of Chinese, Malaysians and other visitors from East Asia also go there as well.
Notable visitors have included NBA Hall of Famer Dennis Rodman, who traveled to North Korea with three members of the Harlem Globetrotters and a team from HBO's hip "VICE" news program.
Many visit North Korea because they're curious about a country that is "one of the few nominally hard-line Communist states still in existence—with all that that entails," said Simon Richmond, coordinating author of Lonely Planet's Korea guidebook. They also go for the bragging rights of having been to a place that very few other travelers visit, he said.
Those bragging rights don't come easy.
"You have to agree to travel in the way the North Korean state wants you to travel and there are lots of rules about what you can and can't do there and how you are expected to act in particular situations," said Richmond.
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But travelers who do go, "and these are travelers, not tourists—get a unique, first-hand opportunity to experience a wildly different way of life than what they might expect," said Julia Cosgrove, editor in chief of AFAR Media, which publishes a magazine and organizes immersive travel experiences.
Despite the fact that a North Korean state-run airline has recently begun selling flight tickets online via a Spanish travel agency, the only official way to visit North Korea as a tourist is on a tour.
"Independent travel is impossible there. You wouldn't get a visa to start with," said Richmond, who noted that most all North Korean tours are arranged by the national travel agency and bought via agencies in Beijing specializing in travel to the Democratic People's Republic of Korea.
A few North American companies organize tours as well, including Mountain Travel Sobek, based in Berkeley, California, which has a trip to North Korea scheduled in 2015 and Remote Lands, a member of the Virtuoso travel network, which offers a variety of trips focused on both urban and rural North Korean experiences, said Cosgrove.
A rise in the number of tourists and tour companies is bringing down costs, lowering the average age of visitors and "incentivizing companies to offer ever more new things to do," said Willoughby. But for U.S. travelers who must first travel to China to begin their tour, the cost of the adventure can still be a deterrent.
And then there are safety concerns, which Willoughby says can be mitigated.
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"Real trouble will come if one is perceived to be proselytizing," he said. "Leave your bible at home so you don't forget it somewhere. Don't brag much about any military service you may have done in opposition to North Korea. And don't take photos of military subjects."
Besmirching any image of the North Korean leadership is a no-no, as is running away from the guide.
That just "causes upset and wastes time," said Willoughby.
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—By Harriet Baskas, special to CNBC.com. Baskas is the author of seven books, including "Hidden Treasures: What Museums Can't or Won't Show You," and the Stuck at the Airport blog. Follow her on Twitter at @hbaskas. Follow Road Warrior at @CNBCtravel.