The Main, with a length of 527 kilometers, is the longest right-hand tributary of the Rhine. The Main's source rivers originate in the Fichtel Mountains (White Main) and the Franconian Jura (Red Main). On the western edge of the town of Kulmbach, in the Melkendorf district, near Steinenhausen Castle, the two source rivers merge to form the Main River itself. Despite many marked changes of direction, the river maintains its main flow direction from east to west – rare in Central Europe – and touches several Franconian low mountain ranges. Large parts of the Franconian wine-growing region and numerous, partly well-preserved, historic town centers lie along the Main. The Main flows through large metropolitan areas around Würzburg and Frankfurt. Opposite Mainz's old town – between Ginsheim-Gustavsburg and the Maaraue in Mainz-Kostheim – it flows into the Rhine. From there (kilometer 0) upstream to above the railway bridge near Hallstadt (kilometer 387.69)[1], the Main (Ma) is a federal waterway. The Main is not exceptionally long, but nevertheless a historically and geographically important river. In late antiquity, its lower reaches between Miltenberg and Großkrotzenburg formed a short section of the outer border of the province of Upper Germany of the Roman Empire. In the 19th century, the Main line separated the spheres of influence of the two major German powers, Austria and Prussia, within the German Confederation, with its seat in Frankfurt directly on the Main. The Main River, which actually runs for long stretches through Upper Germany, is neither a dialect nor a cultural border, but it is widely understood that the Main line divides Germany into a northern and southern part. In terms of transport, the Rhine-Main region is the center of Germany and Europe.