This is a valley of sharp contrasts, with regard to climate and scenery. Ranging from the Burgui Limestone Gorge on the river plain to the Karst mountain landscape of Larra., whilst the Ezka river forms the backbone of this harmonious group of high mountain villages, woodlands and pasturelands.
To the north, lies the Belagua valley, the only glacial valley to be found in Navarre, formed thousands of years ago by one of the ice tongues running from the Larra glacier. Today, this valley is an extensive plain used for agriculture and sheep farming, dotted with fields and huts and completely surrounded by mountains which, in some cases, can reach altitudes of around two thousand metres.
Going up the Belagua Mountain Pass, the scenery gradually changes from flat countryside to woodlands, from woodlands to pasturelands, and from pasturelands to rocks. This all forms part of the Larra Nature Reserve, a tableland dominated by the Mesa de los Tres Reyes summit and the peaks of Anie, Ariás and Lakora. With a height ranging from 1,000 to 2,444 metres and an area covering 2,789 hectares, Larra is one of the most impressive Karst massifs in Europe. Its scenery is dominated by karrens, sinkholes and abysses such as the one at the Piedra de San Martín, making Larra an exceptional spot for caving and potholing. The vegetation landscape is dominated by black pine, rhododendrons, blueberries, junipers, etc. The beech – fir woods are predominant at the lower altitudes. The most typical animals are the brown bear, grouse, Pyrenean mountain goat, rock ptarmigan, grey partridge, white-backed woodpecker, black woodpecker, Tengmalm’s Owl (Boreal owl) and the wallcreeper.