A relaxing cruise along one of Europe’s famous waterways is a surefire way to make the most of your vacation across the pond.Over the last few years, riverboat cruises have grown immensely in popularity, and understandably so. These range in terms of length, price, and the type of boat you’ll be cruising in, from amphibious WW2 vintage “Ducks” (DUKWs) to luxury river cruisers with all the modern conveniences of a modern-day hotel or restaurant.