![Aerial photo taken on April 22, 2019 shows a waterfall in Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China\'s Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)](http://www.ecns.cn/hd/2019/04/23/ab19002a018f4fa5a69447790385ea86.jpg)
Aerial photo taken on April 22, 2019 shows a waterfall in Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China's Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)
![Aerial photo taken on April 22, 2019 shows the Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China\'s Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)](http://www.ecns.cn/hd/2019/04/23/291ae94b14c04351a252bab9d3c3d388.jpg)
Aerial photo taken on April 22, 2019 shows the Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China's Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)
![Aerial photo taken on April 22, 2019 shows the Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China\'s Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)](http://www.ecns.cn/hd/2019/04/23/e0602f1a3a024036aa2ce491a561ddd5.jpg)
Aerial photo taken on April 22, 2019 shows the Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China's Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)
![Photo taken on April 22, 2019 shows a cave of Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China\'s Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)](http://www.ecns.cn/hd/2019/04/23/92ec848dd74645c1befb5ac982c6b620.jpg)
Photo taken on April 22, 2019 shows a cave of Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China's Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)
![Aerial photo taken on April 22, 2019 shows the Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China\'s Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)](http://www.ecns.cn/hd/2019/04/23/95b4aa3262e74ece985f87b94e22f458.jpg)
Aerial photo taken on April 22, 2019 shows the Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China's Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)
![Photo taken on April 22, 2019 shows the crags of Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China\'s Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)](http://www.ecns.cn/hd/2019/04/23/d62cee097ed74eb88062e95411fa628c.jpg)
Photo taken on April 22, 2019 shows the crags of Didonghe Tiankeng, a giant karst sinkhole at Huoshizi Village of Ningqiang County in Hanzhong, northwest China's Shaanxi Province. With a maximum depth of 340 meters, the Didonghe Tiankeng is the largest in Chanjiayan Tiankeng Group in Ningqiang County. (Xinhua/Zhang Bowen)