Port wine (also known as Vinho do Porto, Oporto, Porto, or simply Port) is a sweet Portuguese fortified wine from the Douro Valley in the northern provinces of Portugal. It is often served as a dessert wine. Several imitations of Port are produced around the world in several countriesâ€”most notably Australia, South Africa, India and the United States. However, under European Union guidelines (and in Canada), only the product from Portugal may be labelled as Port. In a similar vein, Federal law in the United States mandates that the Portuguese-made product be labelled Porto or Vinho do Porto. Port is produced from grapes grown and processed in the Douro region, the wine produced is then fortified with the addition of distilled grape spirits in order to boost the alcohol content. The wine is then stored and aged, often barrels stored in caves (Portuguese meaning "cellars") as is the case in Vila Nova de Gaia, before being bottled. The wine received its name, "Port" in the latter half of the 17th century from the seaport city of Porto at the mouth of the Douro River, where much of the product was brought to market or for export to other countries in Europe from the LeixÃµes docks. The Douro valley where Port wine is produced was defined and established as a protected region, or appellation in 1756 â€” thus making it the oldest defined and protected wine region in the world.