December: The Upper Danube River

While late spring is also a lovely time on the Upper Danube, travelers who aren’t averse to colder weather can experience one of Europe’s most festive periods as cities along this legendary river — including Budapest, Vienna, Bratislava, and Passau — transform into winter wonderlands with traditional Christmas markets set in historic squares. Expect plenty of holiday decor, hot spiced wine, and seasonal handicrafts.