Transcript for Life inside North Korea, the hermit kingdom
Reporter: Despite triumphant overtones out of Singapore yesterday -- Great personality and very smart, good combination. Reporter: Millions of north Koreans largely left unspoken for, so far. A country known as the hermit kingdom. Its people closed off from the outside world, long ruled by a family of brutal dictators. A history barely acknowledged between the photo ops. It was painful for us not to mention human rights in the country that may violate them more than any other country in the world. Reporter: I first began reporting on North Korea in 2005 when Kim Jong-un's father was in charge. We expect to show you a country that the world knows very little about. Reporter: On my first trip, the capital was nearly deserted. The urban workers that week ordered to work in the fields. From our visit with young north Koreans -- ?????? to this farm outside the capital, I met with those deeply skeptical of the United States. Their animosity in part stemming from extreme isolation. What do you think about Americans? Reporter: Back then that 18-year-old told us he thought Americans were the sworn enemy of the Korean people. Have you ever met an American before? Reporter: No, he said, he hadn't. I'm an American. Reporter: Forbidden to communicate with the outside world, their only information available, government propaganda. Carefully choreographed scenes like this have been a constant in my visits here. Now it's completely silent. Right up there, Kim jong-il and his song, Kim Jong-un, going to come out and watch. Reporter: More recently, displays of the country's progress. Like their subway system. You can see that this design is an old 30-year-old design -- Reporter: This tour of a gleaming Pyongyang. It was amazing, we've never seen this entire city before. Reporter: This satellite photo taken in 2014 gives a fuller picture of what life in North Korea is really like. The capital, Pyongyang, lit. Everything around it is shrouded in darkness. Hunger and malnutrition are widespread. The U.N. Estimates that more than 40% of the population don't have enough to eat. Food shortages are not new here, but many say it's been exacerbated by tough international sanctions that made it harder to buy food. And there's what's always hidden from view. The country's notorious labor camps. These human rights violations critics say glossed over in the summit. I can imagine north Koreans who have family members in labor camp listening illegally to a shortwave radio, which if they were caught could get their whole family sent to a labor camp, and hearing an American president say that their leader is doing his best for their country, that he loves the country. I would feel incredibly let down. Reporter: Hundreds of thousands of north Koreans have defected. Many fleeing to the south. Risking their lives like this north Korean soldier whose escape was captured by surveillance cameras in the heavily armed demilitarized zone, dmz, stunning the world. As he survived a hail of bullets in order to cross the border. Dr. Lee cook Jon is the surgeon who saved the soldier's life. Transported here from the dmz area. He probably would have died if he was not rescued instantly? That's right. Reporter: After finding safe havens in South Korea, some defectors have been waging campaigns against their former government. With what they say is the most powerful ammunition, the truth. This woman, who goes by the alias miss Han, anchors a nightly radio news show transmitted to the north. Every broadcast a love letter to the ones she left behind. Translator: I like to think my parents and brothers back home are listening to my voice, and they are actually listening to it now. When they hear another defector came and is living here in a free country, how they talk truthfully about democracy, it's a huge shock to them. Reporter: After her father was tortured, she fled across the border to China but was captured by north Korean guards. Translator: I thought I was dead. I'm dead now. Reporter: After her release she paid smugglers to help her try again. She says she became a victim of times as a would-be bride in China. Another high-profile defector, former deputy ambassador to the United Kingdom, described just how cruel the regime can be. They cannot understand that a north Korean system, it is itself a kind of slavery system. I think one day when north Korean system, you know, collapses, I think the whole world will be shocked. Reporter: Now there is hope that this historic summit could be a first step, bringing light to the millions of north Koreans living in darkness. For "Nightline," I'm Bob woodruff in Seoul.
This transcript has been automatically generated and may not be 100% accurate.