The heavily guarded Demilitarized Zone between North and South Korea is impossible to cross alive, so if you want to escape from North Korea, you have a better chance taking the more circuitous route of sneaking into China, and then slowly and cautiously making your way across the country to freedom in South Korea.
But this route presents plenty of obstacles. Defectors have 2,000 miles of China to cross, and if they are discovered by Chinese police, they will be deported in handcuffs and chains back to North Korea, where they will spend 10 years doing hard labor in a prison camp.
Writer Tom O'Neill went undercover to meet some of these North Korea defectors hiding in China, and reported their stories (with names & escape routes changed) in this article in the February issue of National Geographic.
Some 50,000 North Korean escapees are thought to be hiding in China, many of them virtual prisoners of exploitative employers who can blow the whistle on them at any time if they protest. Many of them never make it to South Korea.