Getting the nod from his family, Zheng got down to preparations. He bought items such as a tent, sleeping bags, solar panels and a satellite phone. The two then left their 1-year-old daughter in the care of their parents and hit the road in March 2020. They first flew to Yining, Xinjiang.

"We were filled with excitement about the unknown," he recalls.

They went straight to local farmers and bought two tough horses for 50,000 yuan. Since there are many uninhabited areas in Xinjiang, some of which might have taken them days to cover, Zheng designed a wagon to carry supplies. "The first one was too light and could easily bump off the road."

So he used the steel and chassis of a motor vehicle to build a wagon that weighed about 200 kilograms and attached it to the horses. Yet, it didn't take long before reality diluted their enthusiasm.

"The horses had trouble climbing steep slopes, and we had to empty the wagon and then upload all over again in such places," Zheng says.

Moments of desperation also sneaked up when a wheel of the wagon broke in the middle of nowhere. "It was all exhausting, in terms of energy and money."

Yet, the stunning natural scenery in such places kept them going.

"At dusk, there were clouds all over the sky, which changed from red to purple as the sun shone on them, much like the nebula," Zheng says, poetically.

Such images "move you to tears and make you feel small in the big universe", he adds.