North Korea is one of the world's last closed societies, a communist state that aspires nuclear power and where the people are not free to get in or out.
Dandong lies at the border between North Korea and China, it used to be the city that connected both countries with a bridge at the Yalu river, however the bridge was cut in a half to make sure that there was no more connection with the outside world. The borders or the country are still very much militarized.