Shooting in Xizang is not only about surprises, but also thrills. In 2018, while climbing over and shooting at Tsari Mountain with an altitude of more than 5,000 meters, Niu was struck by hypothermia, hunger and altitude sickness, with no mobile phone signal. Relying only on survival instinct, he spent seven hours inching his way down through deep snow.

"I was on edge the whole time, afraid I might freeze to death before nightfall," he said. At last, when his boots touched softer ground, he saw his Tibetan guide Pema Gyaltsan waiting in a stone hut.

Upon seeing Niu, he went to cut some shrubs and rhododendron branches nearby, poured oil on them to light a fire, and kept fanning it with a portable hand blower. The burning flames warmed the stone hut. A small pot of water, which took great effort to boil because of the altitude, spread warmth throughout Niu's body.

For Niu, every journey to Xizang is not only about recording change but also about reaffirming a truth: friendship and respect can transcend distance, culture and language.

Niu has used his photos from Xizang in his course, Photography Basics, which was rated a "national excellent online open course" in 2018 and included in the first batch of national first-class undergraduate courses in 2020. Some 860,000 students across China have taken the course through online and offline channels, learning from a firsthand view of Xizang's landscapes and culture.