On the two-kilometer coast between the Chinese Cave and Dapu Cave, there is a black rock belt of 1,000 meters long, which is the most famous natural wonder of Jeju Island, the columnar joint belt. The formation of the columnar joint zone is actually the principle of thermal expansion and contraction. When the crater of the Halla Mountain volcano, the highest peak of Jeju Island, erupted hundreds of thousands of years ago, it sprayed a magma with a temperature higher than 900 degrees and rapidly cooled into the sea, so there was The most amazing natural landscape of Jeju Island today. Follow the signs and walk along the boardwalk to the edge of the cliff. One of the platforms is the best place to watch the columnar joints. It is right next to me. Looking closely at the columnar joint belt standing in the sea, I have to marvel at how wonderful the magic of nature is. The sea water slaps on the neatly arranged stone pillars, picking up the white waves, and slamming the shore, leaving only the sound of the waves. Tickets: 2000 won open hours: 9