Mallos de Agüero Nature · Agüero, Hoya de Huesca, Huesca The Mallos de Agüero are a sierra of slightly reddish-tinted conglomerates that closes off the village's valley to the north, with fanciful shapes very similar to the better-known Mallos de Riglos. They have been declared a Geological Interest Point of Aragon and are one of the places where climbing is practised in the area. Photo: McBodes (CC BY 3.0) What to see and do in Agüero