Warrior 4

This is Warrior 4, the largest star destroyer, or rather star dreadnought, and the largest warship in the entire universe.  It is 900 km in length and dwarfs every other type of ship out there.  The Goa'uld ha'tak, the Archangel, the Minerva, the Eternal, Nemesis, The Ark, other star destroyers and other types of ships in existence are nothing to this ship.  Around it are its support vehicles and mechas.  It is in control by the Aliean empire, but the vast majority of the military are not even sure that they do need a ship this as well and of course, the politicians do not want it to exist since they need space colonies more than this.