the Roman Emperor Caligula, like all the decendants of Divine Ceasar, claimed to be decended from Venus and as Emperor he held the Pontifex Maximus, that is the supreme religous office of Ancient Rome.  so it makes sense that on lake Nevi, known to the Romans as "The Mirror of Venus" , an ancient temple site, he would build something special in the Goddesses honor.  but instead of ordinary temple building, it seems he opted to build some kind of enormous naval barge cum temple possibly what is described by Suetonius.

"He also built Liburnian galleys with ten banks of oars, with sterns set with gems, particoloured sails, huge spacious baths, colonnades, and banquet-halls, and even a great variety of vines and fruit trees; that on board of them he might recline at table from an early hour, and coast along the shores of Campania amid songs and choruses. He built villas and country houses with utter disregard of expense, caring for nothing so much as to do what men said was impossible."

Suetonius, Life of Caligula (XXXVII.2)

 

turns out ol' Suetonius was not quite the liar that later ages believed; for the lake has spat out interesting relics for centuries, and by the 19th serious efforts were being made to recover treasures from the sea bed, including the hulls of two vast ships.

Under Mussolini the Nevi ships were completely excavated and put on display, and in the chaos of WWII they were sadly burned.  nevertheless they existed, and they were massive things by the standards of the day.  they featured really unusual details like rotating or moving giant platforms on brass ball bearings, hot baths, running water, mosaics, and heaven knows what all else. 

https://en.wikipedia.org/wiki/Nemi_ships

https://weirditaly.com/2021/10/31/the-bizarre-story-of-the-nemi-ships-built-by-caligula/

and it seems two more have been discovered;

https://www.merlinburrows.com/existence-of-two-further-nemi-ships-claimed-by-merlin-burrows/

So that got me thinking about Renegade Legion's Roman Empire in Space.  If I were a putin like autocrat trying to hold together a massive galaxy wide human imperium with the goal of  keeping humanity safe from aliens while keeping the various principalities from spinning off on thier own by impressing everyone with the obvious superiority of human civilization...I might construct a truely massive ginormous spaceship of near planetary size, and uproot every impressive human archaeological feature, maybe even geological features, planting them into the ship like some massive amusement park cum museum/art gallery/zoological garden.  think the Pyramids and forum, and machu-piccu, and Erhlito, and all of it on display in an environment that also would include the San Francisco Zoo, the Smithsonian, the Hermitage, Seaworld, and probably "cultural displays" of traditional earth ethnicities in a sort of diorama/zoo setting...all in one gigantic moving power and wealth display.  Possibly it would also house the universes greatest university and a massive palace complex.  with this monster propaganda barge you could go from system to system, allowing the hayseeds to have a heavy immersive day of Earth Culture/propaganda, and do honor to local power families by taking their best and brightest youths to "educate" (or hold hostage)... and since you would be travelling with a massive guard fleet, you also get a nice patriotic demonstration of just why you wouldn't want to rebel against the empire...