A second underground hollow space was discovered in Tokyo’s Chofu city ... the time drilling machinery passed under his house. “It is obvious that the tunnel project caused the cavity, ...

Underneath Tokyo’s bustling metropolis lies a maze of concrete tunnels built by Nippon Telegraph and Telephone Corporation to hold telephone and Internet cables. Photo: Alexander Martin/The Wall ...

Japan boasts the world's longest underwater tunnel, which stretches for more than miles under the seabed of the Tsugaru Strait, but it's now barely being used. Work on the Seikan Tunnel was completed ...