TOKYO -- People have excavated beneath the earth from time immemorial: mining for riches, tunneling for transport, and creating spaces for safety and storage.
The country's subterranean world is rich in history and mystery

Tourists can ride a tram in the historic Ashio Copper Mine in Nikko, north of Tokyo.
TOKYO -- People have excavated beneath the earth from time immemorial: mining for riches, tunneling for transport, and creating spaces for safety and storage.