Secret City Beneath Tokyo

Have you ever wondered what may lie under your feet as you walk through the streets of Tokyo? Well, so have I! Many cities in Europe have miles and miles of underground tunnels. Some were built by the government and some were built in ancient times. Those built in ancient times are usually the remains of ancient cities that existed before the present cities were built. Berlin, Paris, London, Rome, and Istanbul to name a few are amazing because there are actually ancient cities underneath the modern cities! But what about Tokyo? Is there anything underneath the city? Well, read this.
After you read the article,(it may be difficult, but please try!), write a short summary and tell me what you think may lie underneath Tokyo. Is there some secret city?

Here are some other websites that document the underground worlds that exist beneath our feet:
Underground England
Underground Berlin
Underground Paris
Underground Istanbul