It's just another day for William Lindesay. It begins by spending some quality time with his sons... and the Great Wall of China. He's lost count of the amount of times he's climbed the wall. However, he still remembers the day he first saw it.

"When I first saw the Great Wall, unbelievably, I was only 11 years old in 1967. I spent a long time trying to work out how long the Great Wall is. I think I failed, but realized it was incredibly long. It would be an expedition, it would take months even years, and I decided, when I grow up, I'm going to do it," said William Lindesay, a Great Wall researcher from UK. 

The UK native came back to China in 1986 with plans to run the wall's entire length - a venture that didn't quite work out that year. Nonetheless, he came back a year later and fulfilled his dream. He then settled in China in 1990. Naturally, he bought a farmhouse at the base of a section of the Great Wall.

"Lots of people say why they are so fascinated by the Great Wall. I think the first reason would be that it's beautiful, and the second thing is that it's outdoors. Everyone thinks they know history and they narrate it to young people. It's so boring. But you know, there is history in the outdoors, and you need to move to discover that. So, it's history alive, or it comes alive in your imagination. Thirdly, it's just fun, you know, what could a man ask for more than waking up every morning, getting up, and doing the thing he really likes and really loves. The Great Wall is in my mind everyday. The Great Wall is a part of our family's daily conversation," said William.

The inspiring location would inevitably play a big role in his children's upbringing. His younger son Thomas Lindesay said, "I often describe my childhood as 'wild', staying at the foot of the Wall almost every weekend , every year. It's incredible because not many people get to see such world heritage all the time, and I got to see all kinds of weathers, all kinds of seasons, with all sorts of different people.”His elder son James Lindesay said, "That adds a lot of influence on how I view the Wall. It's almost like my backyard, so I'm obliged to protect it and enjoy it."

Lindesay has had eight books on the Great Wall published over the course of 30 years. He has also completed three photo projects that show how it has changed over the years. He has also led conservation efforts to protect it. And now his sons are using new methods to spread their fascination with the Great Wall. About four years ago, James and Thomas started using drones to film the Great Wall, which is an entirely new perspective.

"It made me so happy when our drone film - which is really a Lindesay film production - was shown on BBC. I was so happy because for the first time we got an hour and a half to open the eyes of the British people, and tell them, show them what the Great Wall is. We received lots of emails from people saying that they really enjoyed it and didn't know that China was so beautiful. They didn't realize the Great Wall is made of mud with stone and so on. I became a Great Wall ambassador! I like it," said William.

In many ways, the Great Wall has defined Lindesay's life. He even received an Order of the British Empire from Queen Elizabeth II in recognition of his contributions to protecting a piece of the world's heritage. He was also a guest of honor at the celebrations for the 70th founding anniversary of the People's Republic of China. His son Thomas was even at the parade.

"First of all, I would like to do what my Dad did in 1987; run the entire length of the Wall with my brother, so we are calling it 'Two Brothers One Dream', and that maybe a special father's day present," said James Lindesay.

"China has become my home. It is amazing! I found a heaven in the Great Wall's history. The magnificent historical past of China has been opened in front of my eyes. So for me, there is no better place to be than here. Everything I love is here," said William.