North Korea’s motley crew: unlikely visitors to the hermit kingdom (VIDEO)

North Korea may be one of the planet's most secretive nations, but some notable and unlikely visitors have managed to penetrate the hermit kingdom's rigid security.

Famous visitors to North Korea over the years range from Google chief Eric Schmidt to a Cambodian king. As for average folks curious to make the trip, here's some useful advice from the North Korean government itself on travel — Americans, do be careful with that US passport. As for those who've toured the country successfully, here are five of the most noteworthy visits:

1. Dennis Rodman

The infamous American basketball star washed ashore in North Korea this week on a curiously titled "basketball diplomacy" visit, during which he intends to teach young North Koreans the art of shooting hoops.

"It's my first time [to visit North Korea]. I think it's most of these guys' first time. So hopefully everything will be okay, and I hope the kids have a good time for the game," Rodman told Voice of America.

Read more from GlobalPost: Dennis Rodman meets father for first time in 42 years

The trip was organized by the reliably provocative Vice media group, which intends to turn the visit into a documentary to accompany their successful films on North Korean travel.

The North Korea trip isn't Rodman's only Asian connection: the basketball star's estranged father lives in the Philippines, and Rodman recently paid him a highly publicized visit, their first meeting in 42 years.

Here's video of Rodman's dramatic arrival from Voice of America:

2. Eric Schmidt and Daughter

The Google leader decided to pay North Korea a "humanitarian" visit in January alongside New Mexico governor Bill Richardson, the former US ambassador to the United Nations. (The White House was less than pleased about the endeavor).

Schmidt was rumored to be paying a visit at least in part to check out North Korea's decidedly nascent tech and gaming scene — which could explode in line with its southern neighbor's, if the regime ever decides to loosen its current controls on internet freedom.

Read more from GlobalPost: Why is Google chief Eric Schmidt visiting North Korea?

Schmidt's 19-year-old daughter turned out to be the unexpected star of the trip, after the well-spoken teenager wrote about her "very strange" experiences in the hermit kingdom on her blog for Google.

"Our trip was a mixture of highly-staged encounters, tightly-orchestrated viewings and what seemed like genuine human moments," wrote the younger Schmidt of the experience, noting that the group was never allowed out and about without their two minders.

Her father, on the other hand, remained rather less talkative about his magical mystery tour of North Korea.

3. King Sihanouk

The recently deceased Cambodian king, Norodom Sihanouk, was close to North Korean founding father Kim Il Sung ever since their first meeting in 1965, and maintained a state-sponsored residence in Pyongyang during Cambodia's long and bloody civil war years.

Kim Il Sung gave Sihanouk burly North Korean bodyguards, who accompanied the king during his travels around the world. Kim also allowed Sihanouk to make films — one of the king's passions — starring North Korean actors as Cambodia was locked in battle between government forces and the Khmer Rouge.

Here's some interesting footage of Sihanouk's 1971 visit to Pyongyang:

According to writer Helen Louise-Hunter, the Pyongyang palace afforded to Sihanouk was a lavish affair, located on the banks of a man-made lake and equipped with high ceilings and crystal chandeliers — not far from Kim Il Sung's own residence.

A 1992 Deutsche Presse description of Sihanouk's North Korean bodyguards described them rather uncharitably as "trained killers," and noted that over 20 senior DPRK mercenaries had been deployed to protect the Cambodian despot.

In his memoirs, wrote the Telegraph, Sihanouk called Kim Il Sung "my surest and most sincere friend and the most steadfast in my support. Even more than a friend: a true brother and my only 'true relative' after the death of my mother."

4. South Korean filmmakers go on an unexpected — and extended — vacation

Okay, their visit wasn't exactly voluntary, but two kidnapped South Korean filmmakers' extended stay in the DPRK under the auspices of Kim Jong Il ranks among the weirdest incidents in a long history of North Korean strange.

Filmmaker Shin Sang-ok and his actress wife Choe Eun-hui were trapped in Kim Jong Il's summer home against their will in the late 1970s, with Choe Eun-hui kidnapped by the regime first, wrote the BBC.

Sang-ok went to look for his wife and was taken soon after, and they were both kept in North Korea as prisoners, tasked with producing films for movie-loving Kim Jong Il.

They were trapped in North Korea for nearly five years, only able to escape after they traveled abroad in 1986 for a Vienna film festival. They refused Kim Jong Il's offer to return, as the Dear Leader was convinced that the duo had actually been kidnapped by Americans, instead of leaving on their own volition. Shocker.

"I hated communism, but I had to pretend to be devoted to it, to escape from this barren republic. It was lunacy," Sang-ok to the Guardian in 2003.

5. Bill Clinton's Rescue Mission

Two US journalists were trapped in North Korea, and the Obama administration had no sure signs of securing their release. This was plainly a job for Bill Clinton.

The former US president visited North Korea in 2009 on what was widely hailed as a "rescue mission," swooping into Pyongyang on a surprise visit to meet with Kim Jong Il and negotiate for the release of Current TV journalists Laura Ling and Euna Lee.

The two journalists had been caught on the Chinese border and had been sentenced to 12 years of hard labor for their offense, a sentence that many in the US found downright intolerable.

According to the Wall Street Journal, one of the journalists told their relatives that they would be released if Clinton agreed to a diplomatic visit to the unpopular regime, perhaps one of the motivating factors behind the surprise mission.

Much to the surprise of many pessimistic onlookers, the gambit worked: Clinton managed to talk North Korea's leaders into releasing the two women, who returned home to California with him.