Why it's incredible: The cave was created by lava from Mount Fuji and now holds giant ice pillars. The Narusawa Ice Cave is a lava tube that is brimming with icicles and ice pillars at the base of ...
Iceland's Katla Ice Cave is a remarkable work of nature. Sculpted over thousands of years of glacial floods, icy blizzards, and volcanic eruptions, the cave sits inside the Kötlujökull glacier on top ...