There’s plenty on Jeju-do to appeal to those who prefer to be active. Hike up South Korea’s highest mountain, Halla-san, or climb the incredible tuff cone Seongsan Ilchul-bong, rising straight from the sea, to watch the sun rise from the ridge of a crater. For a less-demanding nature experience, meander along one of the Jeju Olle Trails and explore tangerine-trimmed country roads, jagged coasts and narrow lanes dotted with cottage-style homes made from black lava rock.