To date, Li has traveled to almost all regions with Great Wall remains, including Beijing, Inner Mongolia autonomous region, as well as Gansu, Shaanxi and Hebei provinces. He has found over 1,000 km of previously unrecorded sections.

The Great Wall distribution map in Li's computer is dotted with over 10,000 marked spots, each representing a site he has visited.

Li spends over 200 days a year in the wild. He often sustains himself on just one daily meal, usually fried cakes or instant noodles, and sleeps in his car at night.

Every new discovery relieves his exhaustion.

In the summer of 2019, after a five-hour drive through the Gobi Desert in Gansu, he found an ancient city completely untouched without a single footprint in sight. "I was so excited that tears streamed down my face," he recalled.

The adventures also bring risks: Li has encountered wolves, fallen into ice holes, and broken his eyebrow bone.

In 2020, while riding a motorcycle along a gully in a remote canyon, his front wheel sank into soft soil and threw him three meters down a slope.

He blacked out for several minutes before waking up to a sharp pain and realizing his big toe had been broken.

"Just a little further, my head would have smashed into a rock," Li said. "No one would probably have found me if I died there."

However, Li said these physical hardships and injuries pale in comparison to the pain he feels when he sees damage to the Great Wall caused by a variety of factors, ranging from human activities to natural disasters.

Over the years, Li has dedicated himself to protecting the enduring cultural treasure in every way possible.

Many previously unknown Great Wall sections have been placed under protection thanks to the clues he reported to authorities.

He has also persuaded farmers not to remove wall materials for their sheep pens, stopped tourists from climbing watch towers, and reported construction projects that harm the ancient fortifications.

Li's efforts earned him official recognition as a Great Wall guardian in 2016.

For Li, the Great Wall has become an integral part of his life.

He particularly enjoys the nights when he stays alone in the wild — the Great Wall is silhouetted against the starry sky, and nothing but the whisper of the wind and hum of insects fill his ears, bringing him a deep sense of peace.

"I feel as if the Great Wall is watching over me, just as I watch over it," he said.

Xinhua contributed to this story.