The Ahr is one of Germany's northernmost wine regions. It is also one of the smallest, with vineyards extending only 24 km along the Ahr River as it flows toward the Rhine just south of Bonn. From Altenahr, in the west, to the spa town Bad Neuenahr, the vines are perched on steep, terraced cliffs of volcanic slate. In the broad eastern end of the valley, the slopes are gentler and the soils are rich in loess. Four out of five bottles of Ahr wine are red — velvety to fiery Spätburgunder and light, charming Portugieser predominate. Lively, fresh Riesling is the most common white wine produced here. Another specialty of the region is the red variety Frühburgunder.