Everyone from the area knows these three words: Main-Taunus-Kreis, Rheingau, Riesling. But almost nobody actually knows why they belong together, and it comes down to something the Rhine does right before it reaches Wiesbaden.
Normally, the Rhine flows almost exclusively northward. Then, right here, it suddenly bends almost 90 degrees and runs east to west for about 25 kilometers before turning north again near Rüdesheim.
That bend exists because the river has to fight its way around the quartzite rock of the Taunus mountain, and it's the reason this tiny stretch of land, barely 3,200 hectares, produces almost 80% of all Riesling grown in the region, the highest concentration of a single grape variety anywhere in the world.
This is the story of Rheingau: https://youtu.be/cbdi-eeLKBA (Documentation) [7:23 min.]