A couple of weeks ago I mentioned that I'd taken a trip with my family to Yamaguchi Prefecture. The pic below shows the entrance to Akiyoshido, the largest cave system in Japan. (The pics in the previous two posts were taken inside the cave.) The area above-ground is also the largest karst formation in Japan, covering 130 sq. km. and containing over 300 caves. This particular cave has about 1.5 km of tunnels that can be walked through.
Unfortunately it was next to impossible to get any pictures inside the cave (at least with my crappy camera). The ones in the previous posts were taken with the dreaded "night" setting and converted to black and white to get rid of some of the noise and "false" color.
In places the cave really is huge. They could have used it for the Bat Cave. There was a steady stream of visitors, however, so it was hard to get any sense of being in a dark, cavernous space. It would be interesting to be the only person in the cave (and to have really good camera gear).