Yeonmi Park was nine years old when she was invited to watch her best friend's mother be shot.
Growing up in North Korea, Yeonmi had seen executions before. She remembers her mother piggybacking her to public squares and sports stadiums to watch the spectacles used by Kim Jong-il's Workers' Party to silence even the slightest whisper of dissent.
But this killing lodged in her mind. Yeonmi watched in horror as the woman she knew was lined up alongside eight other prisoners and her sentence was read out. Her crime was having watched South Korean films and lending the DVDs to friends. Her punishment in this most paranoid of dictatorships was death by firing squad.
As the executioners raised their weapons, Yeonmi covered her face. But she looked up again, just in time to see an explosion of blood and the woman's body crumple to the ground. "It was a shock," she remembers. "It was the first time I felt terrified."
Yeonmi is recounting the horrific incident over a milkshake in Seoul, the ultra-modern capital of South Korea that is only 35 miles from the North Korean border but, with its luxury cars and 10-lane motorways, feels like another planet. Years have passed since that day, and Yeonmi, now 23, is one of tens of thousands of North Korean defectors who have escaped one of the world's most reclusive and repressive regimes.
Yeonmi has become a globetrotting activist intent on raising awareness about the plight of her people. She appears on South Korean television and uses Facebook, Twitter, Skype and WeChat to spread the word about the human rights abuses inside North Korea.
She has travelled the world to talk about her experiences.
Yeonmi was born on October 4 1993 in Hyesan, a notoriously cold river port along North Korea's 850-mile northern border with China. The following year, on July 8, Kim Il-sung, the country's 82-year-old founder and "Great Leader", died of a heart attack.
Hopes that he might have been ready to gradually open North Korea to the world evaporated as his son Kim Jong-il took power and set about transforming the hermit nation into a member of George W Bush's notorious "axis of evil".
Meanwhile, the economy was collapsing and the Great Famine, which would eventually claim up to 2.5 million lives, according to Andrew Natsios, the former head of USAID, was beginning to take hold. As Barbara Demick describes in Nothing to Envy, her definitive book on the period, those too young, too poor or too honest to find food quickly died.
"The killer targets the most innocent, the people who would never steal food, lie, cheat, break the law or betray a friend."
Yeonmi's father was a mid-ranking civil servant and Workers' Party member who worked at the Hyesan town hall. He kept his family afloat through an illegal sideline in selling gold, silver and nickel (which he had acquired through middle men in Pyongyang, the capital) to Chinese over the border.
That income helped insulate his family from the worst of the suffering as North Korea was plunged into famine. But the bodies Yeonmi saw at the railway station: ragged, skeletal waifs collapsed on the pavement and slumped against walls, told her something was badly wrong. She caught a glimpse of corpses in the river, too.
"I think they were trying to escape," Yeonmi says matter-of-factly. "But they didn't succeed."
Initially shielded from the effects of the famine, Yeonmi's world started to disintegrate when, in 2002, her father was arrested for illegal trading. "Everything changed," she recalls. Yeonmi's father was taken to a prison near Pyongyang and given a 17-year sentence. Her mother visited him once but that was enough to see the toll that the brutal torture had taken on her husband.
He was beaten. Guards placed sticks between his fingers and crunched them together. He was made to sit in excruciating stress positions for interminable periods.
Prisoners were deprived of water and food. "The environment was crazy. So many bugs and lice," Yeonmi says. 'They treated them like animals. He was a really brilliant man. He was my hero, and the country just beat him. I couldn't believe it.'
Yeonmi's father was luckier than many North Koreans who were spirited off to the country's Soviet-style gulags, never to return. According to a Human Rights Watch report in January this year, up to 120,000 political prisoners, among them children, are currently being held in secretive labour camps known in Korean as the kwan-li-so.
Torture including "sleep deprivation, beatings with iron rods or sticks, kicking and slapping, and enforced sitting or standing for hours", is routine, the group found.
After three years Yeonmi's father managed to bribe his way out of jail. But by then he had been diagnosed with colon cancer. When Yeonmi saw him on his release, the once strapping figure had been transformed into a ghost of a man. "He had changed so much.
He was so small. He spoke differently. I couldn't believe it was my father,' she says.
The Park family had been ruined by the imprisonment of Yeonmi's father. Shortly after his arrest they were forced to move from a comfortable house in Hyesan to a minuscule apartment. After his release they almost immediately began plotting their escape into China to start a new life.
But before the family could put its plan into action, Eunmi, Yeonmi's 16-year-old sister, fled across the border with a friend without telling them. Terrified about how she might fare on her own, Yeonmi and her mother decided to follow her over the border and bring her home. Once reunited, the family would attempt a second escape altogether.
And so, on the night of March 30 2007, Yeonmi and her mother made their way towards the border with the help of a people smuggler. Yeonmi's father stayed behind, to minimise the risks. They crossed three mountains and finally came to a frozen river that separated the two countries.
It was desperately cold, Yeonmi says, and she remembers feeling terrified that the ice beneath them would give. But they eventually made it to the other side. On dry land, they ran. "I ran so fast. The only thing I could think was that I could get shot. I ran and ran and ran."
When Yeonmi stopped she found herself in the Chinese province of Jilin. Here, Yeonmi and her mother set about trying to find her sister. But she was nowhere to be found and the local people smugglers refused to help. One even threatened to turn them in to Chinese authorities unless he was allowed to have sex with Yeonmi.
Yeonmi's mother implored the man to leave her daughter alone and offered herself instead. "She had no choice," Yeonmi says. "Literally, in front of me, he raped her."
A few days later Yeonmi's father, who had become concerned about their lengthy absence, slipped across the border and managed to join them. But the family's slide continued. Yeonmi and her parents still had not managed to track down Eunmi but they decided to remain in China rather than attempt a potentially dangerous return to North Korea.
A great-aunt who lived on the Chinese side of the border found them shelter in a filthy, cobweb-filled room in the countryside outside the city of Shenyang. "There was no electricity. We couldn't pay for water,' Yeonmi said. Her parents would collect water from a dripping tap.
It was an experience familiar to the tens of thousands of other North Korean refugees who have escaped to China, one of the world's fastest-growing economies, only to discover a new world of poverty and exploitation. "Even in China we were hungry," Yeonmi says.
The year 2008 was an exciting time to be in China. A construction boom was under way in Beijing as it geared up to host the summer Olympics. But for the Park family the new year brought more misery. At 7.30 one cold January morning, Yeonmi's father died.
Without documents and facing arrest and deportation if they were caught by Chinese police, his family were forced to bribe a local crematorium to destroy his body by night.
At three the following morning, Yeonmi and her mother took his remains to a nearby mountain and secretly buried them.
"There was no funeral. Nothing," Yeonmi says. 'I couldn't even do that for my father. I couldn't call anyone to say my father had passed away. He was 45 - really young. We couldn't even give him painkillers.'
For Yeonmi and her mother, the death signalled an end to their time in China. They took a bus south for two days and spent a short period at a Christian shelter run by Chinese and South Korean missionaries in the port city of Qingdao, which has a large Korean population. When a chance to flee to South Korea via Mongolia arose they seized it, even though they had still not been reunited with Eunmi.
In February 2009 Yeonmi and her mother found themselves deep in the Gobi desert, searching the night sky for the Plough to guide them over the border into Mongolia and towards freedom.
Once there, they could request help from South Korean diplomats who were known to help refugees from the north escaping to Seoul.More than 1,500 North Koreans fled their country in 2012, hoping to build a new life away from the regime of Kim Jong-un, who became Supreme Leader after Kim Jong-il, his father, died in 2011.
Their motives for fleeing are understandable. Earlier this year a UN inquiry concluded that the human rights abuses being committed by Kim Jong-un's regime were "strikingly similar" to those perpetrated by the Nazis during the Second World War. Torture, mass starvation, rape, forced abortion and execution were used as everyday weapons against its 24 million inhabitants, the report claimed.
While a growing number of foreign tourists and international celebrities including Dennis Rodman, the American basketball star, and Pras Michel, the rapper, have recently visited the country, the freedoms of movement, information and belief are still almost non-existent for ordinary North Koreans.
"The gravity, scale and nature of these violations reveal a state that does not have any parallel in the contemporary world," the UN report argued.
But escaping North Korea is far from easy. Refugees who make it to China face discrimination, the constant threat of arrest and, in the case of women, sexual violence, activist groups say. Those who attempt to reach a third country from which to fly to South Korea face deportation if caught, and the penalty for those forced to return is execution or life imprisonment.
That appeared to be Yeonmi's destiny when Mongolian border guards surrounded her group as it meandered through the Gobi desert. They told them they would be immediately sent back to China. Yeonmi and her mother begged for their lives. When that failed, they tried something altogether more radical.
They grabbed the small knives they had brought and thrust them to their throats, threatening to commit suicide unless the guards let them stay in Mongolia. 'I thought it was the end of my life. We were saying goodbye to one another,' Yeonmi says.
Their actions, though, proved effective. Yeonmi and her mother were taken into custody and after 15 days were transferred to a detention centre in Ulan Bator, the Mongolian capital.
Several weeks later they were handed over to South Korean officials and on April 1 2009 - just over a year after the death of her father - Yeonmi stood at Ulan Bator's Chinggis Khaan airport preparing to board a plane for Seoul. It was her first time flying and her new-found freedom had not yet sunk in. "Oh my God," she thought when Mongolian customs officials waved her through. "They didn't stop me."
A few hours later the plane touched down at Incheon airport in Seoul. Yeonmi stepped off the passenger jet wearing a shabby prison uniform. She remembers gasping at the sight of the moving walkways - a contraption unimaginable in her broken and impoverished homeland - and the immaculate lavatory facilities. 'It was the first time I had seen a fancy rest room. I thought, "It's so clean. Do I wash my hands in the [lavatory bowl]?" ' she says. "Everything was shiny. I'd never seen anything like it."
At least 20,000 North Korean refugees have sought shelter in South Korea over the past two decades, and while adapting is far from easy, Yeonmi has fared better than most. She and her mother both worked (as a shop assistant and waitress) so Yeonmi would be able to pay to go back to school. Five years after she arrived, Yeonmi is a third-year student of criminal justice at Dongguk University, one of the city's best, and is a regular guest on South Korean television programmes.
She uses her fame to spread the word about the situation in North Korea and in her spare time has learnt to speak fluent English, with the help of YouTube and the Friends DVD box set. In April she was finally reunited with the sister she had long feared was dead; Eunmi, now 23, had reached South Korea via China and Thailand.
Still Yeonmi feels she has not entirely escaped the clutches of Kim Jong-un's regime. South Korea allocates local detectives to keep an eye on all newly arrived defectors, and in May Yeonmi received a call from the official handling her case.
He warned her that her name had been added to a "target list" of outspoken defectors that the North Korean regime wanted to eliminate. The revelation made her more angry than scared, Yeonmi says. "I crossed the Gobi. I lost my father. But I am still not free. They still have power over me. They still try to control me. Until I can be really free, I will keep going.'
The detective and Yeonmi's mother urged her to stop criticising Kim Jong-un. But she ignored them, convinced that she, as someone who had suffered the same fate, now had a moral obligation to draw attention to the thousands of women risking sexual violence and murder as they tried to escape North Korea.
"I thought about quitting," she says, with a grin that suggests she did not entertain the idea for very long at all. "When I was crossing the Gobi desert I thought nobody really cared, you know?
"Even though I was dying there nobody was going to remember me. These girls too. They are dying. They are being raped. But nobody is going to remember them. Nobody is going to care for them. That is why I thought, 'I'm going to do this and there is no way I will stop doing this.'"
The day we meet, Yeonmi is wearing a startling red dress and a near permanent smile. But the anger she feels towards those who have destroyed her country is clear. "Kim Jong-un and the regime don't just oppress," she says, "they play with human lives. Kim Jong-un should be punished. He must be brought to justice. How many people did he kill?"
One day, she hopes to return home to rebury her father's ashes in a free North Korea. "It was his dream," she says. "It is hard to imagine that day coming but maybe my daughter or my son will be able to do it. Kim Jong-un thinks he can keep going on being a king there. But nothing is for ever."
- This story was originally published in November 2014.