The ground beneath the forest near Mount Fuji is honeycombed with caves and tunnels formed by gas trapped within lava as it cooled. As soon as you start to descend the steps the chill rises to meet you, and once you are actually inside the cave it is very cold indeed. I expected more ice, and I believe there is more in winter, but I went there on a hot summer day. If you visit this cave, you will definitely need at least a jacket. It's freezing down there!
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Find out more about Narusawa Ice Cave.
