The world's largest yacht is also the world's most expensive, with an estimated cost of $1.2 billion. It is owned by Russian billionaire Roman Abramovich, and was delivered to him on December 9, 2010 by it's builders Blohm & Voss from Hamburg, Germany. It is just a little over a foot longer than the 2nd largest yacht owned by the Sheikh Mohammed of Dubai.
So what kind of boat do you get for that much cheese? "The Eclipse". A 536 foot powered island with 2 helicopter pads, 24 guest cabins, 2 swimming pools, many hot tubs, a disco hall (disco?), 3 launch boats, a mini-submarine, a state of the art intruder detection system, a missile defense system, bullet-proof glass, armor plated walls, and a crew of 70 people to run the thing.
Seems a bit much for something you won't spend much time in. I mean who travels by boat these days? Hello. But I guess if you're as rich as Mr. Abramovich then hell, throw in a mall too.