The world's largest yacht has been unveiled and she's so big a new category has been coined for her – 'yacht liner'. 'Somnio' will launch in 2024 and, with a length of 222m (728ft), will be easy to spot from the outside. Only a privileged few, though, will get to view the 500million-euro (£430million/$600million) boat from the inside. That's because she'll serve as a jaw-dropping floating condo for the super-rich ...