What you need to remember is that as the length increases, the size and volume of these vessels increases exponentially – as does the cost to build them. Building costs are closely guarded secrets, often the stuff of rumours and supposition. And when you are dealing with highly designed and engineered masterpieces with features that range from snow rooms to submarines, there is no average cost. It was reported that the 482 foot (147 metre) Prince Abdulaziz, number 4 in the list, was built for $184 million in 1984, while Ellison’s (now David Geffen’s) Rising Sun – number 7 in the list at 453 feet (138.01 metres) – is said to have cost over $290 million to build in 2005. As for resale prices, no one knows how much Ambramovich paid for Pelorus when he bought her from her Saudi Arabian owner soon after she was built in 2003, but rumour has it that Geffen parted with at least $300 million when he bought her last year from Ellison.