The Portuguese DOC area for red and white wines was already defined by law in 1908. The huge area covers 60,000 hectares of vineyards in the districts of Braga, Porto and Viana do Castelo. It stretches 130 kilometres long and 70 kilometres wide in the northwest of Portugal between the Douro River and the Minho River, which forms the border with Spain. The entire area is also classified as Vinho Regional (VR) for Rios do Minho country wines. The cool climate, with an average of 2000 mm of rainfall per year, is very much influenced by the nearby Atlantic Ocean. The area is divided into the six subzones Amarante, Basto, Braga, Lima, Moncáo (considered the best) and Penafiel, which differ in the grape varieties grown. However, the subzone is usually not indicated on the bottle label. The vines are grown in a pergola-like foliage system (tendone). Around a quarter of Portuguese wine is produced here. However, about 60% is produced as simple, unbottled draught wines that resemble cloudy cider. The vineyards are cultivated by around 30,000 winegrowers with very small vineyards, often on a sideline basis.