Jeju Island was created by volcanic eruptions 2 million years ago. As a result, there are places in Jeju that reflect these geographical occurences, including many lava tubes in Jeju. One of these, Manjanggul is a 1km walk through an open-to-the-public lava tube. It was fascinating, walking down those first few steps into the lava tube and feeling the temperature drop suddenly. And then walking through the tube, and reading about the structure and features of the lava tube was educational and interesting. I never even knew that lava tubes existed and it’s pretty amazing being able to walk through the path of the lava from a volcanic eruption.