Video found via Pink Tentacle:
Located 20 meters (65 ft) underground, the 1,480 square meter (16,000 sq ft) space contains emergency supplies to be distributed to the public in the event of a major earthquake. Items include 5,000 blankets, 8,000 rugs, 4,000 candles, 300 cooking pots, 200 t-shirts, and emergency medical supplies. A conveyor belt system is installed to help transport the supplies up to street level.
The underground warehouse is connected to an unnamed station on the Oedo line, Tokyo’s deepest subway. Apparently, the Tokyo Metropolitan Government maintains more than one of these warehouses, but the locations are kept secret.
Now this is the way to be ready for a disaster. And maybe a lesson for everyone in their city - next time you see a key shaped whole in the sidewalk, put you ear down to the cover and listen to the city beneath.
There's a lot going on, underground.