It is said that it was called Baekrokdam because in the old days, hermits came down from the sky and played on Baekrokdam. After circling Baeknokdam, a large volcanic lake with a circumference of about 2,000 meters and a depth of about 100 meters, it is no different from driving around the entire coastal road of Jeju Island. It is 1,950m high. It is the highest mountain in South Korea. It is a dormant volcano that erupted in the late Tertiary to early Quaternary Period. It is made of basalt, and its stem extends east to west from the center of Jeju Island. The south is steep, while the north is gentle, and the east and west are relatively high but flat. At the summit is Baeknokdam, a crater lake with a circumference of about 3 km and a diameter of 500 m. All around it are Mudgeun Oreum, Sara Oreum, Seongneol Oreum, and Eoseungsaeng Oreum. It has about 360 side volcanoes, including Mt. When you climb up the mound, you can feel the height of the mountain and experience the wonderful illusion of floating in the sky. Meanwhile, Hallasan Mountain is designated and protected as a natural monument and Hallasan Natural Reserve.