A largely rural area located inland along the backs of the Oiartzun river, Oiartzun boasts nearby megalithic monuments and mines of Roman origin, such as those in Arditurri, of great archaeological value, as they are considered to be the oldest in the Basque Country. Leaving from Oiartzun to Lesaka or towards Artikutza you will access the Peñas de Aya Natural Park. It is an abrupt area of about 6,100 hectares formed by a granite massif, the only one in the Basque Country. Streams and waterfalls descend throughout the area, as can be found in Aiztondo, spectacular with a 100-metre drop. The area is rich in beeches and oaks, but the fauna is even more interesting: Atlantic salmon, Pyrenean desman, European mink, roe deer, wildcat, vulture, eagle, Egyptian vulture, and kingfisher. It is also home of the hawfinch, which only dwells in this area of the Basque Country.