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 extends over 130 kilometres in length and 70 kilometres in width in north-west 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 climate is cool and very rainy, with an average of 2000 mm of rainfall per year, and is strongly influenced by the nearby Atlantic Ocean. The area is divided into six sub-zones: Amarante, Basto, Braga, Lima, Moncáo (considered the best) and Penafiel, which differ in the varieties of grapes grown. However, the subzone is usually not mentioned on the bottle label. The vines are cultivated in a pergola-like system of foliage (tendons). About a quarter of the Portuguese wine is produced here. However, about 60% of the wines produced are simple wines that are not bottled and resemble cloudy cider. The vineyards are cultivated by around 30,000 winegrowers with very small vineyards, often as a sideline.