The main grape varieties grown in the Rheingau are riesling and pinot noir. The region's special features include the vineyards that stretch southwards down to the Rhine. In the north, the Taunus hills form a protective barrier while the Rhine marks the area's southern border. The Rheingau has a long tradition of winemaking, started by the abbeys many centuries ago. This reputation opened the doors to all the big stately homes for the Rheingau wineries as suppliers of premium vintages. The Rheingau also enjoys an excellent reputation worldwide as the home of the Centre for Viticulture and Oenology in Geisenheim.