http://news.yahoo.com/prelude-worlds-largest-ship-launches-153102193.html

1,601-foot, 600,000-metric-ton vessel, called the Prelude, is a floating liquified-natural-gas facility owned by Shell... 243-foot-wide ship is 150 feet longer than the height of the Empire State Building.

Interesting video of the launch here: https://www.youtube.com/watch?v=TrBSi405Ous

Too bad Shell couldn't build it in the US.