Beginning just below Bonn and extending about 100km (60 miles) south along the banks of the Rhine, the Mittelrhein is a beautiful region of steep, terraced vineyards and some of the wine world’s most splendid scenery – medieval castles and ruins clinging to rocky peaks amid the Rhine Gorge. Nearly three-quarters of the vineyards are planted with the noble Riesling grape. The clay-slate soil yields lively wines with a pronounced acidity, which are often used for making Sekt, Germany’s sparkling wine, where high acidity is an asset.