The Rhine Rift Valley, also known as Upper Rhine Graben, is a unique geographical feature famous for its historic buildings and vineyards. It is part of the European Cenozoic rift system, extending from the North Sea to the Mediterranean. The Rhine Rift Valley is located in the Southwest of Germany and stretches 300 km from Basel (Switzerland) to Frankfurt am Main. The valley is approximately 40 km wide and was formed some 45 million years ago due to a weak point in the earth's crust. The region came under pressure when the Alps arose because of the African and European plate collision. The valley between the Black Forest Mountains and the Vosges Mountains evolved from a sagging surface. There are still numerous but hardly noticeable earthquakes in the region. Even though the Rhine Rift Valley is a geographical feature of Germany, it is hard to distinguish it from a regular river valley.