Znojmo is a great little town in South Moravia, very close to the Austrian border. It lies on the Dyje River so is an ideal launchpad for hikes or cycling trips in the Poddyji National Park. It is a wonderful town to wander around and get lost in its alleyways and as the area is a big wine producing area, you could do a lot worse than spend the evening in a wine bar sampling the local produce.
Znojmo is 280km from Prague and just 70km from Brno. For public transport, have a look at the Czech transport website.
The catacombs are interesting to visit – particularly if the weather is bad.
I’ve stayed in a variety of places in Znojmo and one of the nicest was Pension Grant next to the town’s (beautiful) prison.