Composite of the Saturn V rocket rising from the launchpad as the gantry swings aside.

That giant rocket -the enormous Ares V -would reach a skyscraping height of 381 feet (116 meters) that would surpass the Saturn V and set a new world record.

But there's one future booster that could -when built -steal the "World's Largest" title from the granddaddy rocket of them all, NASA's mighty Saturn V.