
Photo taken on March 26, 2019 shows karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)

ourists visit the Furong Cave in Wulong District of Chongqing, southwest China, March 26, 2019. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)

Tourists visit the Furong Cave in Wulong District of Chongqing, southwest China, March 26, 2019. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)

Photo taken on March 26, 2019 shows karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)

Photo taken on March 26, 2019 shows karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)

Photo taken on March 26, 2019 shows karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)

Tourists visit the Furong Cave in Wulong District of Chongqing, southwest China, March 26, 2019. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)

Photo taken on March 26, 2019 shows karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Lianfen)

Photo taken on March 26, 2019 shows karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Lianfen)

Tourists view the karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China, March 26, 2019. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Dong Jianghui)

Tourists view the karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China, March 26, 2019. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Dong Jianghui)

Photo taken on March 26, 2019 shows karst landscape inside the Furong Cave in Wulong District of Chongqing, southwest China. The Wulong Furong Cave was listed as a UNESCO world natural heritage site in 2007. (Xinhua/Liu Chan)