A cruise down the Rhine and Moselle rivers in Germany turns up some awe-inspiring sights, none more so than the dozens of fairytale medieval fortresses, writes Catherine Masters.
What a terrific experience day three is turning out to be. We're motoring along the Rhine aboard our luxury floating hotel the Panorama with amazing castles dotting the hills, all magical with their turrets and flags and jolly colours, looking just like the ones in kids' picture books.
As we marvel, cruise guide Andrezj fills in the medieval and not so magical blood-soaked history of this world heritage area.
We've been given a list with 25 or so unpronounceable names of the castles we are going to see crammed into two hours of solid castle-watching along the Rhine Gorge, a 64km section of the 1327km river which winds through Germany.
What a treat ... but I'm getting ahead of myself.
The start of "castle day" had already been fascinating, albeit in a strange sort of way. We had docked at the little wine town of Rudesheim. The morning was a stunner, beautiful and clear, and after the usual hearty Panorama breakfast we set off on a shore visit to the town of only 10,500 residents but which swells with tourists as the day progresses.
Swans sailed past on barely rippling water and a "choo choo" (Andrezj's word) arrived to take us up the cobblestoned streets, past cafes, tourist shops and little houses with shuttered windows to our surprising destination, Siegfried's Museum of Mechanical Musical Instruments (website in German).
Guides greeted us in their olden-day dresses, almost manically cheerful as they ordered us from room to room, to keep to a strict schedule and allow for all the other groups to follow.
Our guide began by telling us we were going to explore how people used to have fun in the days before CDs and she cranked up a weber-maestro. Things whirred and clanked and loud, thumping music pumped out, which she jigged along to. The next piece was a symphonium, much quieter, so this time she swayed and hummed.
This went on for many pieces of musical equipment, including one called a Gebrüder Bruder Waldkirch which thumped out Big Top music from the former wine cellar of a creaky old Germanic house.
We wandered the rooms in a sort of stunned awe and just as I was thinking it would be a great setting for a Vincent Price film she led us into a room to see a very strange "beautiful orkestra". This turned out to be puppets in fancy dress holding instruments, silent and staring and just a little freaky.
When she wound them up the the monkeys and dolls started playing cellos and violins and moved their heads. Eeek. I was quite pleased to get outside into the sunshine.
Happily the spell was broken by a visit to a nearby cafe where cheerful oom-pah musicians greeted us and served coffee with a huge amount of cream on top and the town's famous asbach brandy, 40 per cent alcohol, perfect for blasting through the chill of the morning.
By the time we got back on the boat, strangely hungry enough to eat yet another huge lunch served on the top deck, the excitement was becoming palpable. Just ahead were all those castles ... and now here they are, one after the other.
Andrezj warns us the excitement may wane - it's a hell of a lot of castles - but who really can complain about sitting on a comfy boat watching medieval castles of an afternoon?
I'm not going to begin to name them all and I have to confess that after trying to photograph each one I mostly have no idea which is which. They do all blur a bit (I popped downstairs to get a jacket and missed three castles) but have in common a glorious splendidness.
Andrezj says that in the past Germany was a union of independent Germanic states and every local ruler, lord, duke or king, wanted his own castle. Little towns grew around the castles on their hills, which is why their names often have berg (hill) or burg (castle) or furt (fort) in them.
Barges go speeding by as regularly as the castles, on the Rhine, as this is also a working river. Often the captains live on their boats, sometimes with their families, and you'll see cars parked on board and the washing out as they transport all manner of cargo - coal, iron, diesel, cereals, sheet metals, chemicals.
We take a sharp bend to pass through the most famous part of the Rhine Gorge. This is where, so says the legend, the beautiful Lorelei used to sing atop a craggy hill, combing her haid and luring captains to their death.
Many accidents have happened at this bend with its treacherous cross currents and whirlpools but we safely navigate them, leaving the Lorelei behind, and go on to more castles.
Apparently, captains had to stop and pay tolls at every castle. Despite the Lorelei, the river was still safer to travel than the road as there were robbers and zealots hanging out in the lush green forests. A fair amount of carnage went on up in the hills, though today it is so quiet on the river you can hear the birdsong and distant bells ringing.
Up ahead is a particularly grand yellow castle, Stolzenfels, the only one not to have fallen to enemies. A little later the castles come to an end as we pass a giant statue of Kaiser Bill and pull up at the town of Koblenz.
It's still only day three but there's just enough time for a quick shore visit before dinner back on board and another sail away to another picturesque town.
On day four I'm awake at 5.10am and look out of my panoramic window as we chug along. The river has narrowed and the houses loom closer and closer, and the ever-present vineyards are set into even more impossibly steep hills, some with long ladders which seem to be the only access - what a back-breaking job picking the grapes must be.
We're on the Moselle now, just off the Rhine, and pull up at Cochem, another tiny town, with 6000 inhabitants but a whopping two million tourists a year.
Before a leisurely and of course huge breakfast, I take a stroll on the upper deck and gasp out loud. Wahoo! Just there up on the hill looking down on its village is a castle and this one we get to go inside.
Onshore, we attach to another guide who tells us Cochem Castle was built 1000 years ago but was destroyed 350 years ago.
She points out a little tower which is the only original bit of the castle left. This is the witch's tower where many a poor woman was tested to see if she was a witch: she had to jump off the tower; if she lived she was definitely a witch so she was killed but if she died she wasn't a witch - but it was all a bit too late by then.
Most of the castle was destroyed in 1689 by Louis XIV of France. In fact, it seems nearly all the castles between here and Heidelberg were blown up and burnt down and have been restored.
This one was in ruins for years until a rich businessmen bought it for a song for his family but in 1942 it was sold to the Third Reich thanks to exorbitant taxes which basically forced the sale. The Nazis didn't end up using the castle, though, and since 1978 it has belonged to the town.
It's fabulous with secret doors and rooms still displaying some of the previous owner's belongings. That would be Louis Ravene who "enjoyed his life", our guide says, and would use the secret doors to nip up to the maids' quarters. After all the fairytale sights of the past few days nothing surprises us.
Einstein is gesturing madly and thwacking bits of wood together, cracking jokes and generally making the invention of printing a wildly interesting process.
Of course, the man racing around the mini-stage in the Gutenberg Museum in Mainz is not really Einstein, but as the woman next to me said, he does a pretty good nutty professor imitation.
George Buchleitner is wearing a small moustache, a vest and coat, tartan-patterned trousers and does rather shout his enthusiasm in a strong German accent. He's also our guide for a stop-off in the ancient German city of Mainz, one of many such visits in the course of our river cruise through the heart of Europe, all of them illuminated by marvellous local guides.
The enthusiasm he pumps out brings alive Mainz, first showing us old black and white photos of before and after the Allies bombed the city in 1945, destroying nearly 80 per cent but leaving the cathedral standing. The first thing people did was look in the direction of the cathedral "because as long as the cathedral is not lost, Mainz is okay".
Mainz is really on the map, though, because of its most famous son, Johannes Gutenberg, born about 1400, who invented the first printing press which revolutionised the production of books. Some of his printed bibles are on display at the museum in a softly lit room.
George tells how it took monks three years to handwrite one of these but Gutenberg was printing 160 in the same length of time. Gutenberg was a genius, he says, but not too good a businessman. He took out a huge loan but couldn't pay the instalments, went bankrupt and lost everything.
Next he fixes a slightly bored-looking woman with a stare and says, "You are so fascinated by Gutenberg that you ask me spontaneously where is Gutenberg buried."
To cut short a long George reply to his own question, 1945 had presented the perfect conditions for archaeology, due to most of the city being rubble, so people searched where they thought his grave was, only to find the skeletons of monks but none labelled the man himself.
"Alas," says George, "Gutenberg is lost." But not, happily for us, the story of the man and his city.
Further information: Avalon Panorama has two decks of spacious suites, each with a lounge area and wall-to-wall, floor-to-ceiling panoramic windows which open to give the feeling of an open-air balcony.
Avalon's 15-day Magnificent Europe Panorama itinerary takes in the Rhine between Budapest and Amsterdam.
Fares for next year start from $5910 per person twin share. Nearly everything is included in the price, including tips for the crew, complimentary wi-fi, all meals, wine with meals and the excellent shore tours.
See the Avalon Waterways website for more information.
Catherine Masters travelled the Rhine courtesy of Avalon Waterways