Feldkirch is one of Austria's best-preserved small medieval towns, tucked into the western edge of Vorarlberg where Austria nearly touches Switzerland and Liechtenstein at the same time. It is not as famous as Bregenz, but the old town has more immediate charm: arcaded streets, narrow lanes, city gates, and the castle of Schattenburg looking down from the hill.
The town makes an easy half-day trip from Bregenz, but it also works as a quiet base for the Rhine valley. Trains are frequent, Liechtenstein is just across the border, and the mountains rise quickly behind the suburbs. Feldkirch's appeal is that it still feels like a border town in the old Central European sense: compact, practical, a little hidden, and full of routes leading elsewhere.
Start in the old town around the Marktgasse, climb to Schattenburg for the view and museum, then look into Feldkirch Cathedral and the Montforthaus if there is an exhibition or concert on. If you have more time, the road and bus routes south and west lead quickly toward Liechtenstein's castles and the wooded hills above the Rhine.