Narusawa Ice Cave: A lava tube filled with 10-foot-tall ice columns at the foot of Mount Fuji.

The average annual temperature in Narusawa Cave is around 37°F, which contributes to the permanent ice cover. (Photo: amana images inc. via Alamy) KEY FACTS Name: Ice Grotto Narusawa Hyoketsu Location: Fuji Five Lakes Region, Japan Coordinates: 35.475766342241734, 138.6658965143265 Uniqueness:…