Straddling the banks of the picturesque Danube river, Wachau is known for producing some of the best dry white wines in the world. The region is also home to a large number of impressive medieval fortresses, monasteries, and castles, and has been designated a UNESCO World Heritage Site because of its natural beauty and cultural importance. Wachau is located only an hour or so from Vienna and it's possible to visit the area as a day trip from the city; many different companies offer extensive tour packages that include a boat ride along the river.