Photo taken on July 14, 2019 shows a part of Yunsheng building, an earth fort, in Bayi Village of Xiaotao Township, Yong'an City, southeast China's Fujian Province. Built in 1859, the earth building called Yunsheng is a protected historical site of the city level. (Photos: Xinhua)

Tourists visit Yunsheng building, an earth fort, in Bayi Village of Xiaotao Township, Yong'an City, southeast China's Fujian Province, July 14, 2019. Built in 1859, the earth building called Yunsheng is a protected historical site of the city level.

Photo taken on July 14, 2019 shows a part of Yunsheng building, an earth fort, in Bayi Village of Xiaotao Township, Yong'an City, southeast China's Fujian Province. Built in 1859, the earth building called Yunsheng is a protected historical site of the city level.

Photo taken on July 14, 2019 shows a part of Yunsheng building, an earth fort, in Bayi Village of Xiaotao Township, Yong'an City, southeast China's Fujian Province. Built in 1859, the earth building called Yunsheng is a protected historical site of the city level.

Aerial photo taken on July 14, 2019 shows a part of Yunsheng building, an earth fort, in Bayi Village of Xiaotao Township, Yong'an City, southeast China's Fujian Province. Built in 1859, the earth building called Yunsheng is a protected historical site of the city level.

Tourists visit Yunsheng building, an earth fort, in Bayi Village of Xiaotao Township, Yong'an City, southeast China's Fujian Province, July 14, 2019. Built in 1859, the earth building called Yunsheng is a protected historical site of the city level.