Keywords: Wulongtianshengsanqiao.JPG 重庆武隆的天生三桥,世界自然遗产武隆 斯特的组成部分 <br> Sanqiao Tiankeng collapse of a river cave roof off Wulong at River Wu; provincial-level municipality of Chongqing before 1997 part of Province Sichuan Own Brookqi 2008-11 location possible Wu Gorge Wu River Chongqing Karst topography in China South China Karst Three Natural Bridges |