Many of Europe's great cities owe their existence to the waterways that link them. A sublime way to see them is by boat, write Ben and Joanna Hall.
For centuries, they were the continent's main highways and instrumental in the development of its culture and architecture. These days Europe's rivers provide passage for one of the fastest-growing sectors in the travel industry.
The latest figures show 11,761 Australians took a European river cruise in 2007. This represents 4 per cent of the total cruise market, a figure that is increasing each year due to the rise in group travel on the waterways.
The reason is simple. In a single day of cruising Europe's rivers, it's possible to take in medieval villages with citadels, monasteries, castles and cathedrals, separated by a landscape of stunning mountains and farmers at work herding sheep or picking grapes.
As ocean cruisers know, sailing from one destination to another is a leisurely way to travel. You drop your luggage in your cabin for the duration, wake up in a new port each morning and at the end of the day, you can meet with new friends at the bar onboard to swap stories as the boat glides to the next destination.
Cruising in Europe is a fantastic experience that captures some of the world's great coastal cities. River cruising, however, provides access to a heartland, which is more serene and rustic. That's not to say there's a shortage of classic cityscapes on the waterways with the likes of Amsterdam, Vienna and Budapest on many itineraries but this type of tourism is more about smaller towns and villages off the beaten track that are less likely to be overrun with tourists.
Flowing through the heart of Europe are the Rhine, Main and Danube rivers, spanning 3500 kilometres from Amsterdam on the North Sea, to Romania on the Black Sea. Although it is possible to cruise from one side of Europe to the other - a river voyage that takes 24 days - most first-timers venture out on week-long Danube cruises, which take in Germany, Austria and Hungary.
A typical cruise starts in Vienna, one of the most romantic cities in Europe which inspired Mozart and Strauss to compose many of their best works. Many itineraries schedule two days in the Austrian capital to allow a proper exploration. Further down the Danube, the small medieval town of Melk features an array of architecture from the past 1000 years and the town's abbey, called Stift Melk, towers over the countryside as one of the world's most famous monastic sites.
Austria's third-largest city, Linz, straddles both sides of the Danube and is an interesting blend of a modern cityscape with medieval architecture, while the Old Town of Passau in Bavaria and the ancient city of Regensburg are two of the most popular ports in this region.
Many cruises include Nuremberg, which allows for a transit though the engineering marvel of the Main-Danube Canal and its amazing system of locks.
Other popular European rivers for cruising include the Seine in France, Portugal's Douro River, the Po River in Italy, the Elbe from the Czech Republic to Germany, the Volga in Russia, and the Rhone and Saone with excursions to Provence and its wine country.
Although the onboard experience of river and ocean cruising share some similarities, the size of the vessels and what they offer is a major point of difference. While ocean-going ships can carry between 500 and 3500 passengers, river boats rarely take more than 200 and can be as small as only 20 or 30.
They're also built low to the water to pass under ancient and medieval bridges, being able to dock in the centre of small towns that the bigger vessels can't access.
Staterooms and cabins are usually a lot smaller on river boats and have functional bathrooms and a few private balconies.
Facilities and entertainment are limited in comparison to mega-liners. Don't expect grand cabaret shows or a choice of restaurants; there's usually one dining room with assigned seating to suit groups and, if you're lucky, there may be a solo pianist or harpist playing through the evenings. Swimming pools are a rarity, although demand from passengers is prompting some companies to upgrade vessels.
A major bonus of river cruising is the absence of tendering (ship-to-shore transfers on small boats), as the boats dock right in the heart of the towns and villages, making it possible for passengers to walk on and off at their leisure to go exploring.
In larger groups this can be a godsend; if some people don't feel like charging around, or want to do something different, they can do their own thing with ease. As for seasickness, this isn't really an issue on a river cruise, even for a first-timer who isn't familiar with the state of their sea legs.
The European river cruising season is in full swing in the northern hemisphere summer, although spring and autumn are becoming more popular as the change of seasons creates an alluring landscape. Increasingly, Christmas cruises are appearing on the itineraries of some companies, as they offer the chance of experiencing the fairytale image of Europe covered in snow, with the bonus of Yuletide markets in quaint villages.
Cruising the high seas on an ocean liner may capture the romance of a bygone era of travel but, as many travellers discover, river cruising has many benefits. It's also a leisurely and time-efficient way to experience the heart of Europe and get up close and personal with its famous history and architecture.
BEFORE YOU BOOK
* If you are new to cruising, or river cruising in particular, play it safe and opt for a shorter itinerary.
* Be aware that river cruises tend to have busy schedules. You will be in at least one port of call every day and won't have the "sea days" you get on ocean cruises.
* Always check what's included in the fare. Although accommodation, food and some tours will be covered, in many cases any transfers, tipping, soft drinks and alcohol will be extra.
* If you need to keep in touch with work or your family during your trip, be aware that most river boats are yet to offer internet access.
* Your cruise may start and finish in a different European country, so you may need to budget for flights back to your port of embarkation.
* Check with the cruise company for any pre and post-cruise tour options, as these are often an affordable way to enable you to extend your trip.
* Children and solo travellers can be an issue. Generally cabins are too small to accommodate more than two people and very few, if any, boats have facilities for kids. Solo travellers may also find they have to pay a supplement to travel.
10 TOP SPOTS FOR RIVER CRUISING
* The Nile, Egypt On the world's longest river, cruises operate between Luxor, home of Egypt's most famous temples, and Aswan in the south.
* The Yangtze, China Cruising this historic waterway is a wonderful way to see a large part of this fascinating country in a short amount of time. Popular routes include the famous Three Gorges Dam.
* The Amazon, Brazil and Peru Exotic and breathtaking, cruise ships can navigate the lower and central sections as far as Manaus but the narrow and more remote upper Amazon is river-boat territory.
* The Mekong, Vietnam and Cambodia A cruise here offers a glimpse of the diverse history and exotic cultures of two very different countries. Highlights include visits to Ho Chi Minh City and Angkor Wat.
* The Mississippi, US A cruise along "Ol' Man River" from Memphis to New Orleans explores historic sites such as Vicksburg and the Cajun heartland of Baton Rouge.
* The Douro, Spain and Portugal This beautiful waterway meanders through villages, market towns and past vineyards. Highlights often include the ancient Spanish city of Salamanca and Pinho in the heart of the Portuguese wine country.
* The Brahmaputra, India One of the world's lesser-known river-cruising spots, wildlife and wilderness are the main highlights here, in particular India's national parks, including the stunning Kaziranga.
* The Irrawaddy, Burma Flowing from north to south and into the ocean, this cruise combines natural beauty with the chance to explore the legendary Mandalay.
* The Murray, Australia The mightiest river Down Under flows from the Snowy Mountains to the Great Australian Bight, offering some gorgeous scenery and stunning experiences along the way.
* The Caledonian Canal, Scotland This spectacular waterway in northern Scotland connects the North Atlantic with the North Sea, with highlights including a climb along "Neptune's Stairway" under the shadow of Ben Nevis.