I saw this on some other blog via my new aggregator, and ment to post on it but it slipped my mind. So thankfully now I get a second chance. Antipixel posts about an book published last year that suggests there is a secret city hidden underneith Japan. It sounds like there's a conspiracy about the whole thing also.

Sitting on the Ginza subway from Suehirocho to Kanda, he says, you can see many mysterious tunnels leading off from the main track. “No such routes are shown on maps.” Traveling from Kasumigaseki to Kokkai-gijidomae, there is a line off to the left that is not shown on any map. Nor is it indicated in subway construction records.

At Tameike-sanno on the Ginza Line, the first basement level is closed off, for official use only. “Go to the toilet on B2 and there is a door to B1, but locked.”

It really does sound like something out of a conspiracy thriller. Hmm, maybe there's some kind of secret city under Boston. That's why the Big Dig has taken so long.