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
Nabro Volcano exact nature of the activity is unknown, but activolcans.info noted that there might be a lava lake there. Nabro Volcano The Nabro Volcano is a stratovolcano in the Southern Red Sea Region of Eritrea. It is located at the south-east end of the Danakil Alps in the Danakil Depression. Before its 2011 eruption, the volcano was widely believed to be extinct. Part of the Afar Triangle, the Nabro Volcano is one of many volcanic caldera complexes in the northeasternmost part of the East African Rift valley region. The twin calderas likely formed during an eruption of about 20 to 100