Fugaku Fuketsu Wind Cave

Fugaku Fuketsu Wind Cave runs 201 meters beneath the Aokigahara forest in a passage formed by a lava flow from Mt. Fuji. The walk through the cave and back takes about fifteen minutes at a relaxed pace. Inside, signposts point out lava shelves where the molten wall peeled off as it cooled, curling like wallpaper to the floor. The deepest section stays at a constant 3 degrees Celsius year-round. Until the mid-twentieth century, this natural cold was put to use: shelves here stored silkworm larvae in winter, tricking them into thinking spring had arrived whenever they were removed, making year-round silk production possible.