The rainy Glasto swamp has nothing on Boryeong city in the Chungcheong province, three hours from Seoul, which has 9.9million square metres of squidgy brown mineral-rich mud on nearby mud flats. In July it's put to good use in the form of mud slides, mud fights, mud baths, mud wrestling, mock battles and rodeo rides for a festival at Daecheon beach. All good clean fun.