The wine-growing sector in Spain is one of the most important in Europe and is classified with the highest quality level DOCa (Denominación de Origen Calificada). Although a large part of the vineyards, 62,000 hectares, are located in the northeastern Spanish province of La Rioja, part of it is also in the provinces of the Basque Country (Subzone Alavesa) and Navarre (parts of Subzone Rioja Baja). The area has a very old viticultural history. Numerous fermentation vats carved in stone have been preserved, testifying to wine growing as far back as ancient times. The most typical are the guardaviñas found in Rioja Alta in Ábalos, Briones and San Asensio. These dome-like stone constructions were used as shelters for winegrowers and their livestock in bad weather and for monitoring the harvests.