Long before ultra-running became popular, William Lindesay embarked on a wacky solo mission to run the length of the Great Wall - an adventure that saw him endure fiercely painful blisters, live in constant fear of arrest, and risk the possibility of a lonely and painful death in the wilderness.
The Briton ran the entire 2,500-kilometre distance without a support crew, often in intense heat on sections that were far from the nearest settlement. This year marks the 25th anniversary of that epic journey, one that saw Lindesay detained nine times by local police, and, at one point, suffer the ignominy of deportation.
The run was split into two parts, during the spring and autumn of 1987, to avoid the more extreme heat of mid-summer. Lindesay had been to the Great Wall the previous year with the intention of running its length, but realised he had massively underestimated the difficulty of the challenge, particularly the searing temperatures of July and August.
He set out nonetheless, and was quickly laid low by amoebic dysentery and a stress fracture. But there was one positive discovery during that shortened expedition: Lindesay was surprised to find that peasant farmers living by the wall were hospitable people, willing to provide a bed and sustenance once they overcame their initial shock at seeing a gangly European stranger jog into the village.
Lindesay returned home to England and plotted another assault for the following year - this time with better preparation. The keen club runner already had the athletic credentials for an ultra-endurance mission - he had a marathon time of two hours, 39 minutes and a nippy 10-kilometre personal best of 31 minutes, 30 seconds.
What's more, Lindesay had a passionate desire to become the first person to run the length of the Great Wall, even though it meant risking life and limb.
Says Lindesay: "People ask me if I ever got lost, and I say I was always lost. It is only when I got to bigger places that I knew where I was. I knew this was my last chance, and this time I was prepared. But there were risks - journalist friends told me that I could find myself in serious trouble.
"One time it was really hot weather, and I ran 40 to 50 kilometres in one day. My feet started to blister, but I kept going. In fact the blisters burst and the skin welded to the socks. It was like running on knives. When I stopped, it was like having knives rammed into my feet. When I got to a town, the doctor lanced the blisters and put iodine on. It was nasty.
"At one point during the run, I was deported from China. I simply got new passport and visa in Hong Kong, and came back. The system was not so sophisticated in those days, so the different provinces could not correlate all the different 'offences' I had committed.
"Ordinary people were very helpful. They would think nothing of letting a stranger into their home - and a Western one at that. At one place, they gave me a room and the whole village came to see me, to look at this person from another planet.
"They were amazed that there were other kinds of people in the world who could speak another language. I showed them a picture of the queen I had picked up at Heathrow, and told them that this was the leader of my country. They thought she was my mother."
The epic adventure started in far-western Gansu province, where the wall is actually ramped earth, rather than the 16th-century stone structure near Beijing that most people are familiar with. Lindesay ran on the wall wherever he could, or alongside in the parts where it had crumbled. The expedition ended at the evocatively named Old Dragon's Head, where the wall meets the sea.
As a schoolboy, Lindesay had announced plans to visit the Great Wall, producing chuckles from his teachers and classmates. But the ambition stayed with him into adult life.
He says: "I had my heart and mind set on it, and although I realised there were real risks, I believed I might just be lucky. It was a major adventure to a place that was little known. In fact, the moon was more familiar - I could name more places there than in China."
Lindesay ended up spending most of his adult life in China. He wrote the best-selling book, Alone on the Wall, about the expedition and began making a living from wall-related activities such as writing books, giving lectures, and conducting weekend walking tours from his farmhouse home, close to an isolated part of the Great Wall some two hours from Beijing.
Lindesay and his wife Wu Qi have two sons, Jimmy and Tommy. He estimates he has spent 1,600 days of his life on - or close to - the wall.
The Briton's indefatigable work to help preserve this wonder of the world has brought him honours from the Chinese government, an OBE from Queen Elizabeth, and universal admiration as an explorer par excellence. "The Great Wall is an outdoor museum that collides with modern China and the developers head on," says Lindesay. "It is a unique conservation challenge."
Lindesay, now 55, stays in shape with regular strenuous hikes along the wall. He has even started some gentle jogging, perhaps inspired by thoughts of his groundbreaking run a quarter of a century ago.
His feelings about the wall have not changed he says: "At the end of the run, I thought it was an amazing wall. I still think the same way."