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
Volcano Pompeii. Before its catastrophic eruption of 1991, Pinatubo was an inconspicuous volcano, unknown to most people in the surrounding areas. Two other examples are the long-dormant Soufrière Hills volcano on the island of Montserrat, thought to be extinct before activity resumed in 1995, and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE and had long been thought to be extinct. The three common popular classifications of volcanoes can be subjective and some volcanoes thought to have been extinct have erupted again. To help prevent people from falsely believing they are not