Riesling grapes grow particularly well on the slopes of the Mosel Valley and is tributaries. The Ancient Romans made the most of the warm climate to harvest grapes here. As well as storing heat, the slopes give the wine its unique taste. Riesling grapes are also grown in the winemaking area of the Palatinate or "Pfalz” - one of the largest in Germany with over 3,600 vintners. It produces a quarter of Germany’s wines. Running through the area is the German Wine Route, one of the oldest tourist trails in the country. Over in Franconia, vintners specialize more in the Müller-Thurgau and Silvaner varieties. This region has its own trademark, flattened wine bottle form.