With its crater (Baeknokdam) rising to 1 950m (the highest point in the country), the Hallasan volcano casts a shadow over the 360 so-called secondary volcanoes, which, together with the tens of kilometres of lava tunnels, caves and curious coastal mineral formations, have been declared a UNESCO World Heritage Site. Nearly 2 000 species of plants grow on its slopes and in valleys. A geological and plant spectacle that can only delight hikers with every change of season.