Natural Park of the Sierra and Canyons of Guara Nature · Nueno, Hoya de Huesca, Huesca The Sierra y los Cañones de Guara Natural Park extends across the comarcas of the Alto Gállego, the Hoya de Huesca, the Sobrarbe and the Somontano de Barbastro, in the province of Huesca, and covers fifteen municipalities, including Nueno. With 47,453 hectares and a peripheral protection zone of a further 33,286, it is the largest natural area in Aragon, with altitudes ranging from 430 metres beside the río Alcanadre to the 2,077 metres of the Guara peak. Its geology has shaped a network of canyons, ravines and gorges carved by water, making it one of the great references for canyoning in Europe; notable are the gorges of the río Balcés, more than 20 kilometres long, and the Grallera Alta de Guara sinkhole, with a 277-metre vertical drop. It was declared a natural park in 1990. Photo: Deivid (CC BY-SA 3.0) What to see and do in Nueno