Yaohui Dong and two friends finished an epic trek along the Great Wall of China in September 1985.
Through snow storms and arid deserts, they relied on local villagers for food and water as they documented every step of the wall, parts of which hadn’t been walked on for years.
Their journey inspired a protection and restoration effort which continues today.
Witness: The stories of our times told by the people who were there.
Article source: http://www.bbc.co.uk/news/magazine-41240113