What could ever top this wonder of the world, this building widely considered to be the world's most beautiful? Anything, surely, would be a major let-down.
Uniworld's latest river-cruise ship Bon Voyage has just set sail in France's Bordeaux wine region. Brian Johnston is there to see whether it lives up to its name.
Ensure the smoothest of sailings with these useful tips and insights into cruising etiquette for the virgin or even veteran cruiser.
River cruising is rife with spine-tingling moments and this, it's safe to say, is definitely one of them.
Under the darkened small top, just as the latest performance of Phare, the Cambodian circus, is about to begin, there's a minor commotion in the packed audience.
"This is going to be your best cruise ever," says our guide. "Because you're in West Africa, the happy place."
Wurzburg's baroque palace and history is only topped by a cold glass of the Franconia region's favourite drop, silvaner.
For those who travel to see places rather than sit on ships, cruising is getting ever more interesting.
Put these dates in your diary.
Blessings abound in villages along Myanmar's Irrawaddy River.
Glide peacefully through the World Heritage-listed Tasmanian wilderness of Gordon River where convicts once built magnificent Huon pine ships.
The best thing about these moments is that they happen again and again when you know where to look for them.