The search giant sent several photography crews to shoot long exposures of several popular underground (natural and man-made) formations in Japan. The two areas include the centuries-old Okubo-mabu mineshaft (part of Iwami Ginzan) and massive Akiyoshi-do limestone cavern, available for viewing via the Street View interface. Click on the galleries above; 360-degree views of silver, stalactites, and stalagmites await your eyeballs...