A look inside the world's most luxurious, powerful and gigantic cruise ships as they function like cities on the sea, ferrying thousands around the globe.

A look inside the narrow cruiser that fits through tight locks, battles nasty weather and glides past stunning scenery, travelling from Budapest to Amsterdam.

A look inside the world's most luxurious, powerful and gigantic cruise ships as they function like cities on the sea, ferrying thousands around the globe.