Police station in cave: One of a kind

In the summer, temperatures in the region can reach as high as 45 C while in the winter, they can drop to -25 C, usually accompanied by strong winds of up to 88 kilometers per hour.

After explorations in the park, they chose an earth mound and began to dig with their simplest tools, including shovels and pickaxes, in May 2001.After a year's work, they had excavated a space of 40 square meters.

"We called it our first-stage project," said Li. "By June 2017 we had finished the construction of a 260-square-meter station, including office rooms, a dormitory, a bathroom and a dining room."

Under such tough conditions, the police officers stuck to their official task of preserving order in the park and protecting the safety and property of tourists.

Over the past 24 years, Li and his colleagues completed 170 rescue missions and rescued 21 people who found themselves in danger.