Cities that you should have seen once for a long weekend in Lower Austria are:
St. Pölten - provincial capital with baroque old town, Art Nouveau facades and cultural district around the Festspielhaus and Museum Niederösterreich; located directly on the Traisental cycle route
Krems an der Donau - historic old town in the UNESCO World Heritage Wachau with Steiner Tor, small galleries and wineries; ideal starting point for stages on the Danube cycle path and the Welterbesteig Wachau World Heritage Trail
Baden near Vienna - spa town with Biedermeier old town, spa gardens, casino and Beethoven, part of the "Great Spa Towns of Europe"; located on the Thermenradweg/Helenentalradweg cycle path, with popular hikes through the Helenental valley and into the Vienna Woods
Melk - baroque Melk Abbey overlooking the Danube and a small, atmospheric old town; directly on the Danube cycle path and close to stages of the Wachau World Heritage Trail and hikes in the Dunkelsteinerwald forest
Retz - wine town with a large main square, wine cellar labyrinth and windmill; starting point for numerous wine cycle routes through wine cellar lanes and vineyards as far as the Czech Republic
Wiener Neustadt - town between the Middle Ages and modernity with castle and Kasematten; junction of the Thermenradweg cycle route and ideal starting point to the Vienna Alps with hiking areas such as Hohe Wand and Schneeberg
Zwettl - Kuenringer town in the Waldviertel with a historic centre and Hundertwasser fountain; a hiking village surrounded by river paths along the Kamp and Zwettl rivers, supplemented by regional cycle paths and the Kamp-Thaya-March route
Waidhofen an der Ybbs - "City of Towers" with Schloss Rothschild and the 5 Elements Museum, riverside paths and favourite places along the Ybbs; located directly on the Ybbstal cycle path and surrounded by hiking trails in the Mostviertel region, for example in the Buchenberg Nature Park
Tulln an der Donau - art and garden city with Danube promenade, DIE GARTEN TULLN and Egon Schiele reference; lies on the Danube cycle path and is the starting point for cycle tours through the Tullnerfeld and walks and trails in the Danube floodplains