All throughout Aokigahara, Japan’s so-called Suicide Forest, are underground caves that were formed by volcanic activity from the nearby Mount Fuji. If you ever go exploring, you may just fall into one.
One of the largest and most impressive of these lava caves is the Narusawa Hyoketsu, or Ice Cave. There are stairs leading down into the 70-foot-deep cavern and areas where you must crouch to get through. Once you reach the bottom, the ice is crystal clear and stunning, catching the color-changing light beautifully.
The ice is there year-round, with large icicles growing throughout the cave sometimes up to 3 feet long. Located on the edge of the Suicide Forest, also called the Sea of Trees, Narusawa Hyoketsu is designated a Natural Monument of Japan.