REUTERS/Damir Sagolj
A tourist looks into North Korea from a tower on the Chinese side of the border between Russia, left, China, center, and North Korea, right, near the Chinese town of Hunchun, November 24, 2017.
Life along North Korea's northern borders with China and Russia stands in stark contrast with the southern frontier it shares with South Korea.
While the southern border is marked by the heavily fortified demilitarized zone, long stretches of the border with China only have some surveillance equipment or barbed-wire fences in various stages of disrepair.
Reuters correspondents Damir Sagolj and Sue-Lin Wong traveled along North Korea's northern border in November and March this year. They peered across the frozen rivers that separate the countries, catching glimpses of life in the hermit kingdom.
But they also encountered strict Chinese security and areas where China's military seemed to be up to something - activity that observers said was in preparation for turmoil in North Korea.
"Border regions anywhere in the world are sensitive, but it's particularly sensitive up here because the river is narrower and historically there has been a lot of interaction between the two sides," said Li Zhonglin, a China-North Korea specialist at Yanbian University.
Below, you can see what life is like on North Korea's remote northern frontier: