A research institute has released a 3-D geological map showing the underground structure of Tokyo's 23 wards designed to help residents think about weak areas and better prepare for earthquakes.

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 ...

Tokyo Underground Women's Prison CHAPTER 4・Area ∞ Tokyo Underground Women's Prison CHAPTER 1 · Area 88 ...

Currently – when the metropolis is not threatened by rainfall – the impressive underground infrastructure serves as one of ...