With a dictatorial regime, a powerful security apparatus and ruthless crackdown on dissent, what goes on in North Korea has long remained a secret for much of the rest of the world. But one journalist was given a rare opportunity to explore one of the world's most repressive countries while her own identity was kept secret.

Suki Kim, an American journalist born in South Korea, told HuffPost Live's Josh Zepps on Tuesday how she got involved teaching 50 students whose families were part of Pyongyang's elite.

Though Kim had traveled to North Korea before, she spent six months in Pyongyang in 2011 undercover, finding a job as a teacher at the all-male Pyongyang University of Science and Technology. She explained the bizarre agreement behind PUST; it was founded by a Korean American Christian evangelical under the agreement that teachers inside the school would not proselytize, a crime punishable by imprisonment.

She told HuffPost Live the school was under intense surveillance by the military. "I was watched 24/7. The school was bugged, so there wasn't really any way to show anything out in the open," Kim said.

Her students, whom Kim described as "lovely," were unaware of the school's religious affiliation. But they knew she was a foreigner and that they weren't allowed to show much curiosity about the outside world. When they did subtly ask her questions about life beyond North Korea, she was afraid to answer because she didn't "know what danger it posed for [them]."

"They had never heard of [the] Taj Mahal or Eiffle Tower, or things that we take for granted, they just did not know," Kim said. "So it was really overwhelming, I think, and frightening to think about how little they can do or know."

Kim Jong Il died on her second-to-last day in the country, and she explained the chilling experience of interacting with her students amid the news.

"It really was [like] a parent had died and the sky had fallen,"she said.

When Kim returned from North Korea, she penned her experience in a new book, Without You, There Is No Us: My Time with the Sons of North Korea's Elite.

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