The government trusted the company to turn the Zhangbi Castle and the tunnel into a national-level tourist attraction in 2009. Today, the castle generates 10 million yuan in ticket sales revenue annually.

The company's role change also benefited many local villagers who used to depend on the coal industry for survival.

"I feel relaxed selling tourism souvenirs here," said villager Li Qijin. Li used to be a coal miner in the city. "Men and women in the village now rely on tourism," he said.

The central government is also encouraging social capital to protect relics, with a State Council guideline emphasizing the role of social capital.

However, the inflow of social capital also increases the risk of damages to cultural relics. To enhance supervision, authorities are building a digital platform where all local cultural relics will fall under their watch.

"This will allow us to prevent any relic vandalism," said Zhao Shuguang, the Shanxi culture relics official.