The most notable of all Portuguese wine regions is Douro Valley, named after the river in the northern part of the country. It is a historical wine region which has become very famous over the centuries as the birthplace of the fortified Port wine, although it gains popularity for its dry white and red wines from port grape varieties. The region is known for its beautiful steeply terraced vineyards overlooking the Douro River, which flows in the Atlantic Ocean. The climate is hot continental with influence from the Atlantic and the river as well which has a much greater impact of the microclimate of the region, which is separated in three subregions until it reaches the Ocean. It was the first region to be specified with borders in 1756 by the Prime Minister Marquês de Pombal to protect its uniqueness. There are three sub-areas in the region each covering a section of the river as it flows toward the town of Oporto. Douro Superior sub-region is found in the more inland side of the river with around 20% of the vineyards. Cima Congo sub-area is located in the central part of the river, and it is recognised for the best quality Port wine with almost half of the plantings of the region. And the last is Baixo Corgo situated on the coast the best suitable for still wines. The main grape varieties of the region for red wines are Touriga Nacional, Tinta Roriz (Tempranillo in Spain), Tinta Barroca, Trincadeira, Tinto Cão, Touriga Franca and for whites are Sercial, Gouveio, Viosinho, Malvasia and Rabigato. The grapes for Port wine and still wines are the same as sometimes for the still versions are used Cabernet Sauvignon, Sauvignon Blanc and Gewürztraminer from the non-local grapes. The Douro Valley was elected World Heritage Site by UNESCO in 2001.