SpaceX has completed what's known as the 'stacking' of its first Super Heavy prototype, the extremely large next-generation first-stage rocket booster that it will eventually use to propel its Starship spacecraft to orbit and beyond. The Super Heavy Booster is about 220 feet tall – which is roughly the wingspan of a Boeing 747, or a bit taller than the Cinderella Castle at Walt Disney World in Florida.

That's without Starship on top, which will add around another 160 feet. Super Heavy will undergo its own testing prior to flying with Starship, however, and a lot of that will be focused on assuring its fuel tanks can handle the pressurization and extreme temperatures required for keeping all that ignitable material stable prior to when the engines actually fire.

Super Heavy uses the same engines as Starship — Raptor engines, to be specific, which SpaceX created new for this generation of launch vehicle. The final version will have a total of 28 Raptor engines, but this first prototype will likely be outfitted with far fewer, and SpaceX CEO Elon Musk has confirmed that it'll also remain grounded, as it's intended to be use only for testing things like build and transportation mechanics.