The Wachau is the most beautiful stretch of the Danube in Austria, a narrow valley between Melk and Krems where the river winds between steep hills covered in vineyards and forest, with castles, abbeys and villages on its banks. It is a UNESCO World Heritage site in its own right. Near the village of Aggsbach, on the southern bank, a small Roman watchtower stood in the Blashausgraben, a side valley, as part of the Danube frontier of the Roman Empire.
The Danube was the northern frontier of the Roman province of Noricum, and the Romans built forts and watchtowers along its banks to control traffic and watch for raids. The Danube Limes in Austria was added to the UNESCO list in 2021 as part of the Frontiers of the Roman Empire. The remains of the watchtower in the Blashausgraben are modest, but there are better-preserved Roman remains elsewhere in the Wachau, such as the fortified tower in Bacharnsdorf and the fort in Mautern.
Above Aggsbach, on a rock high above the river, stand the ruins of the castle of Aggstein, once the lair of robber barons who preyed on Danube shipping. Upstream, the Baroque abbey of Melk, a vast yellow building on a rock above the river, is one of the most famous monasteries in Europe, with a magnificent library and church. Downstream, Dürnstein, with its blue church tower and ruined castle, where Richard the Lionheart was held prisoner on his way home from the Crusades, is the most visited village in the valley.
The riding along the Wachau is very pleasant, though it can be busy. The roads on both banks follow the river, with gentle bends and wonderful views of vineyards, castles and the water. The southern bank is quieter. The roads climbing out of the valley into the Dunkelsteiner Wald and the Waldviertel offer more challenging riding, with tight bends and forest. In spring and autumn, traffic is lighter.
Aggsbach has a few inns, and Melk, about seven kilometres away, has fuel. The Wachau is known for its apricots and its white wines, Grüner Veltliner and Riesling. Spring, when the apricot trees blossom, and autumn are the best times to visit.