Bog of Las Dueñas Nature · Cudillero, Avilés, Asturias Twenty-six hectares of peat bog declared a natural monument on 25 July 2002, a rare ecosystem beside the sea because this kind of wetland is common in the mountains. It nurtures mosses, carnivorous plants, marsh violet and arnica. Photo: Ramón (CC BY-SA 2.0) What to see and do in Cudillero