China completes first high-speed rail tunnel under the Yangtze River

China has completed the first high-speed railway tunnel under the Yangtze River, the Caiyuanba Yangtze River Railway Tunnel. This 11.9-kilometer tunnel, finished on Friday, connects two districts in Chongqing. It is a crucial component of a future high-speed rail line intended to link inland China with its coast, specifically connecting Chongqing to Xiamen in Fujian province. The construction faced significant challenges due to Chongqing's complex geography, including tunneling under mountains, residential areas, and riverbeds. This achievement represents a significant advancement in the development of China's high-speed rail network.