In summer, in addition to the beach, Koreans will count the Donak Valley. Jeju locals will bring a big watermelon to Donak to enjoy the cool. The Donak Valley is very, very cold, but this cold is not cloudy, it is cool to walk in, so everyone takes watermelon to ice. The downstream section of the valley is well-equipped and it is more convenient to walk; the upstream section is more natural, but the steep road is slippery. Girls in the valley wet feet just fine, the stream is clear but too cold for the body.