Max Pearson

And I try to imagine them and what sort of lives they had.

Yao Huidong has spent his life studying the wall, and on September 24, 1985, he and two friends became the first people ever recorded to walk the entire length of it, well over 8,000 kilometers.

It was an adventure that took them 16 months, but the inspiration for it had developed over years.

When I was in my 80s,

In the early 80s, I was an electrician, installing high-voltage power lines.

But in my spare time, I was also really into literature, and I would write my own stories and poems.

I could see the Great Wall from my house.

I found it really inspiring, and I'd always think, how did they actually build it?

At the time, there were hardly any books written about it, but I wanted to find out everything I could about its history.

The Great Wall began as a collection of walls and battlements, originally built to stop marauding armies and nomadic gangs from raiding villages and towns in the north of China.

The first emperor of a united China, Qin Shi Huang, started the construction more than 2,000 years ago.

It also served as a road, linking hill forts in mountainous areas and making it easier to deploy soldiers to trouble spots quickly.

I began to notice that different parts of the world looked different, and they were built differently.

I learned that different armies had built sections over time, and I began to think, I bet no one has ever walked along the whole thing before.

And I thought, if I could do that, and document what I see, well, that would be a really meaningful contribution to our nation's history.

Also, the first complete set of footprints along it would be mine.

Just thinking about it made my heart beat faster.

Leaving his wife and their young baby behind, Yao Huidong set off with an old school friend, Wu Deyu, in May 1984.

They started on the east coast at Shanghai Pass.

Before long, they were joined by another wall enthusiast, Zhang Yuanhua, on what was to become an epic journey for all three of them.