One of the more charming ports of call during our seven-night cruise was on the Moselle River. Heidelberg docked within a 5-minute walk from the city center of Bernkastel and within a 20-minute walk (with a moderate grade) to the castle ruin of Burg-Landshut that overlooks the city. The community's wine-growers tend Germany's largest continuous expanse of vineyards. Needless to say, the wines here are heavenly.