The cultural landscape around the southern Moravian castles of Lednice (Eisgrub) and Valtice (Feldsberg) is one of Europe's largest, the product of centuries of care by the Liechtenstein family. Both castles are very nice - at least from the outside, since you had to take a guided tour to see them, and these were evidently only in Czech... Anyway, the gardens and ponds are really very nice for a relaxing stroll and going there makes a great daytrip from Vienna (only about an hour or so by train).