Crazy Tunnel Project of China

China is preparing to build the world's longest submarine tunnel.
China has developed itself in the field of technology and has begun to sign quite effective projects. The Chinese government, which has started to work for a crazy project, is preparing to build an 123 submarine tunnel to connect the Dalian city in the northeast of the country to the eastern city of Yantai.
The project will cost 42 billion dollars and is expected to pay off in 12 annually. In fact, this project was previously thought of in 1994, but the tunnel was not expected to be completed in 2010. If the project takes place, the distance between the two cities will be reduced to 1000 mileage.
For now, the longest tunnel is in Japan with a length of 54 kilometers. The Seikan tunnel connects Japan's Hokkaido and Honshu islands.