Photo taken on July 3, 2019 shows the landscape inside the Xueyu Cave in Fengdu County of Chongqing, southwest China. The Xueyu Cave, also known as Snowy Jade Cave, is a national 4A scenic area famous for its crystal clear stalactites. (Photos: Xinhua/Liu Chan)

Photo taken on July 3, 2019 shows the landscape inside the Xueyu Cave in Fengdu County of Chongqing, southwest China. The Xueyu Cave, also known as Snowy Jade Cave, is a national 4A scenic area famous for its crystal clear stalactites.

Photo taken on July 3, 2019 shows the landscape inside the Xueyu Cave in Fengdu County of Chongqing, southwest China. The Xueyu Cave, also known as Snowy Jade Cave, is a national 4A scenic area famous for its crystal clear stalactites.

Photo taken on July 3, 2019 shows the landscape inside the Xueyu Cave in Fengdu County of Chongqing, southwest China. The Xueyu Cave, also known as Snowy Jade Cave, is a national 4A scenic area famous for its crystal clear stalactites.

Photo taken on July 3, 2019 shows the landscape inside the Xueyu Cave in Fengdu County of Chongqing, southwest China. The Xueyu Cave, also known as Snowy Jade Cave, is a national 4A scenic area famous for its crystal clear stalactites.

Photo taken on July 3, 2019 shows the landscape inside the Xueyu Cave in Fengdu County of Chongqing, southwest China. The Xueyu Cave, also known as Snowy Jade Cave, is a national 4A scenic area famous for its crystal clear stalactites.

Photo taken on July 3, 2019 shows the landscape inside the Xueyu Cave in Fengdu County of Chongqing, southwest China. The Xueyu Cave, also known as Snowy Jade Cave, is a national 4A scenic area famous for its crystal clear stalactites.