Fuji Fuketsu (a lava tunnel)' designated as a natural treasure is located in Aokigahara Forest. In the cave, it's always kept 0℃ and has many mysterious icicles. I found many things that I had never knew in the explanation by the local guide! You can bring back the interesting stories.
Shoji Fujikawagushiko-cho, minamitsuru-gun, yamanashi