In May1984, three friends starting trekking along the Great Wall of China. It took 508 days for them to complete and they became the first people to do it.

They finally reached their destination at the Jiayu Pass on 24 September 1985, having documented the condition of the wall every step of the way.

The men became national heroes, as the press followed their progress. Dong Yaohui spoke to Rebecca Kesby in 2017 about the inspiration for their journey.

Eye-witness accounts brought to life by archive. Witness History is for those fascinated by and curious about the past. We take you to the events that have shaped our world through the eyes of the people who were there.

For nine minutes every day, we take you back in time and all over the world, to examine wars, coups, scientific discoveries, cultural moments and much more.

Recent episodes explore everything from how the Excel spreadsheet was developed, the creation of cartoon rabbit Miffy and how the sound barrier was broken.

We look at the lives of some of the most famous leaders, artists, scientists and personalities in history, including: the moment Reagan and Gorbachev met in Geneva, Haitian singer Emerante de Pradines’ life and Omar Sharif’s legendary movie entrance in Lawrence of Arabia.

You can learn all about fascinating and surprising stories, like the invention of a stent which has saved lives around the world; the birth of the G7; and the meeting of Maldives’ ministers underwater. We cover everything from World War Two and Cold War stories to Black History Month and our journeys into space.

(Photo: Dong Yaohui, Wu Deyu and Zhang Yuanhua. Credit: Dong Yaohui)