>> North Korea is a closed country, so it's easy to forget that travelers from both the north and China have long crossed their shared border. That includes the thousands of North Koreans who have defected to the south. Many first crossed here, and the Chinese have put up a lot of barbed wire to try to stop them.
However, this border is 1,400 kilometers long, and that means it's very hard to completely shut down crossings.>>
> There's definitely still secret trading, we're so close and if you have a boat then you're definitely gonna do it. It's definitely happening.>> I'm writer Sue-Lin Wong. Along with Photographer Damir Sagolj, I drove along the border.
Security was tight, but people told us they've interacted for years with North Koreans across the river. It is just how porous the border is with a big hole in the fence. When people can back and forth trading wood, for grains and other agricultural products. Behind us, we can hear the loudspeakers from the North Koreans, as well as farmers calling to their animals.
North Korea was once wealthy. Now, life on the other side is hard. Damir took this photo of a guard watching women wash clothes in a freezing river. Chinese traders told us that North Koreans wash all kinds of things in that river, vegetables, clothes, and themselves. When it freezes over like this, people have to break it up to go on with their daily lives.
Some did it without wearing gloves. The north now lives under hard sanctions. And ties with China had grown rocky. However, there are 15 official crossings. I found they were sometimes the most tense. And just behind me is the Tumen bridge which is one of the more popular border crossings of people going In and out of North Korea.
Tumen is considered a more sensitive city, because the river's narrower here and it's easier for North Korean defectors to cross into China. Many living here are still closely connected. But even in the age of nuclear sanctions, China can't totally crack down. If Beijing cuts ties too sharply, it could destroy North Korea and spark a million strong exodus.
If they are too welcoming, it could unleash the same thing.