You remember the Eclipse, the 560-foot long yacht by Russian gazillionaire Roman Abramovich. It is the largest private yacht in the world. But maybe that claim is hard to visualize... until you see it compared to a 747.

More than double the size of the Jumbo, in fact. Not big enough for you? It is even bigger than the Corellian Corvette used by Princess Leia:

Except the Eclipse doesn't carry Leia, but Darth Vader. [Iconwerk via ffffound!]