Active & Discovery on the Rhine (Southbound)

Budapest, divided by the Danube into the hilly Buda of thermal baths and medieval castle lanes on one bank and the grand Pest of coffee-house culture and Art Nouveau splendor on the other, delivers the most theatrical first impression of any European capital — whether approached by river as the neo-Gothic Parliament materializes from the water or by night from the Citadella's sweep of illuminated panorama below. The city's celebrated thermal bath culture, rooted in Ottoman-era hammams and perfected in palatial Secession-era pools like the Széchenyi, is an experience entirely unlike anything else in Europe. Visit spring and autumn for comfortable temperatures; Vienna is two and a half hours west by train.

Budapest, divided by the Danube into the hilly Buda of thermal baths and medieval castle lanes on one bank and the grand Pest of coffee-house culture and Art Nouveau splendor on the other, delivers the most theatrical first impression of any European capital — whether approached by river as the neo-Gothic Parliament materializes from the water or by night from the Citadella's sweep of illuminated panorama below. The city's celebrated thermal bath culture, rooted in Ottoman-era hammams and perfected in palatial Secession-era pools like the Széchenyi, is an experience entirely unlike anything else in Europe. Visit spring and autumn for comfortable temperatures; Vienna is two and a half hours west by train.

Koblenz stands at the Deutsches Eck — the German Corner — where the Moselle river pours into the Rhine in a confluence so geographically commanding that the Romans built a fortress here in 9 BC. The result is a city of exceptional Rhine Gorge scenery, with the formidable Ehrenbreitstein Fortress, one of Europe's largest, crowning the opposite bank and reachable by gondola for panoramas that stretch across three river valleys. A Rhine wine tasting at one of the city's historic Weinstuben, followed by a stroll through the Altstadt's baroque squares, is the definitive Koblenz afternoon. The finest weather arrives April through October, with the Rhine in Flames fireworks festival in August being particularly spectacular.

The port of Vienna is a cultural gem along the Danube River, famous for its stunning architecture, rich history, and vibrant culinary scene. Must-do experiences include sampling authentic Wiener Schnitzel and visiting the picturesque village of Dürnstein. The best season to visit is spring or early fall, when the city's gardens bloom and outdoor activities abound.

Krems an der Donau has stood at the eastern gateway of the Wachau Valley — Austria's most beautiful stretch of the Danube — since Emperor Otto III granted it market rights in 995 AD, making it one of the country's oldest documented towns. The UNESCO-listed Wachau landscape surrounding the city is a masterpiece of vineyard terraces, Baroque abbeys, and medieval castles reflected in the river; the Grüner Veltliner and Riesling wines produced here are among Austria's finest. Must-dos include visiting the monumental Melk Abbey and cycling the Danube Cycle Path through the valley. Krems is most enchanting April through October, with the harvest season in September offering wine cellar tastings of exceptional depth.

Passau occupies one of Central Europe's most dramatic natural stages — a narrow peninsula at the confluence of three rivers, the Danube, Inn, and Ilz, where the old town's baroque spires and shuttered merchants' houses crowd the very tip of the land between the waters. St. Stephen's Cathedral houses the world's largest church organ, a 17,974-pipe instrument whose daily concerts fill the nave with a sound that seems architectural in its density. The Veste Oberhaus fortress above the city commands panoramic views across three countries on clear days. Passau is a classic Danube river cruise departure point; spring and early autumn, when the river runs high and the light turns golden, are the finest seasons.

Regensburg, Bavaria's medieval masterpiece on the Danube, is one of Central Europe's most intact ancient cities — its Roman origins visible in the Porta Praetoria stone gate, its medieval prosperity celebrated in the soaring twin towers of St. Peter's Cathedral and the twelfth-century Stone Bridge. UNESCO World Heritage status acknowledges a skyline dotted with patrician towers, while the famous Historische Wurstküchl, Germany's oldest operating sausage kitchen, has been serving spit-grilled bratwurst since the 1140s. The surrounding hills produce excellent Bavarian whites. May through September offers the most convivial riverbank atmosphere.