China announced a plan to build the longest underwater tunnel of the World on 14 February 2014. Water tunnel will be constructed beneath the Bohai Sea.
The 123-km long underwater tunnel will connect the port cities of Dalian in Liaoning province and Yantai in Shandong province. The project will cost 36 billion dollar to construct the shortcut between two northern port cities in an earthquake-prone region.
The work on tunnel is expected to start from 2015 or 2016 and is expected to be completed by 2026. Once complete, it would drastically cut the current travel time between the two cities to about 40 minutes, which are currently separated by a 1400-km drive or about eight hours by ferry.
The tunnel would surpass the combined length of the world's two longest tunnels, Japan's Seikan Tunnel linking Honshu and Hokkaido and the Channel Tunnel between Britain and France.
Three tunnels in total will be built at least 30 metres below the sea bed, two about 10 metres in diameter, and a third between them for maintenance and emergency vehicles.