The story focused on river cruise travel operated by lines familiar to North Americans such as Peter Deilmann, Viking River, Grand Central Travel and Avalon Waterways. Other key metropolis' that lie on the river cruise routes include places like Berlin, Vienna, Lyon, Budapest, Prague, Amsterdam, Venice, Brussels and even St. Petersburg and Moscow -- all built on and around the rivers that have served them for generations.
And while river cruising is increasingly widening its audience to attract big ship cruisers who are drawn to Europe's heartland (and want to limit the long bus rides) it's worth noting that big ship options do exist -- even when it comes to the biggest cities lying some distance inland. The challenge is that many of them, with the exception of Amsterdam and Venice, require a significantly long shore excursion due to distance from major port hubs. For instance, cruise travelers spying Paris, Berlin or London on ship itineraries may be surprised to find that their actual ports are in Le Havre, Warnemunde or Southampton/Harwich/Dover respectively. All are at least an hour plus (and in most cases even further) from those magnet cities.
Because cruise traffic to those major cities is harder to quantify by those big ships that do visit these places, there's no easily available info on which is "most popular". For cruise travelers who want to spend time in Europe's land-bound major metropolises, cruisers' best bet is to look for routes that start or end in places that are embarkation ports -- like Venice, Barcelona, Rome, London or Amsterdam -- and spend a couple of extra days there before or after their voyage.
Paris, alas, is rarely -- if ever -- used as a port of embarkation.