Narusawa ice cave

The Narusawa Ice Cave is a lava tube located in the Aokigahara forest, in the part that belongs to Narusawa Village, Yamanashi Prefecture, Japan. It is one of the three larger lava tubes at the northern foot of Mount Fuji, the other two caves being Fugaku Wind Cave and Lake Sai Bat Cave. All three were designated as Natural Monuments of Japan in 1929.

The Narusawa Ice Cave is 156 meters long measured along the visitor route with two lobes, with the width of 1.5 to eleven meters and the height of one to 3.6 meters. The average temperature inside the cave is about 3°C.

Source: Wikipedia