Hallasan National Park (9.6 km), Seokgulam Trail (1.5 km), Gwaneumsa Trail (8.7 km), Donnaeko Trail (7 km), and Eoseungsaengak Trail (1.3 km). The longest trail is Seongpanak Trail which takes about 4.5 hours. Hallasan comprises 153.112 km of the Jeju Island. It rises 1.950 m above the sea level which means the highest mountain in South Korea. This mountain was formed in the fourth Cenozoic era by outburst of volcano. It is mostly composed of basalts. It is extending east and west, and it has high and gradual descent. On the other hand, the south part of the mountain is steep. In the
Kell (volcano) Kell (volcano) Kell () is a small extinct Holocene stratovolcano. It is located just north of the Zheltovsky volcano, within the Prizrak caldera on the southeast coast of the Kamchatka Peninsula in Russia. Because of its remote and inaccessible location, most information about the volcano comes from aerial surveys. The volcano was discovered during an aerial survey in 1946. The Prizrak caldera has a diameter of about 4 km. It is located on top of the site of an ancient stratovolcano whose base has a diameter of about 10 km. The slopes of the caldera feature a network of erosional