The Fleet

A collection of ships travelling through interstellar space, large enough to support a population of about 1 million humans. 

They are made up of 4 Great Ships plus 64 lesser ships.  A majority of the time, the lesser ships are docked onto the great ships, acting as suburb-like neighborhoods.

Ships

The 4 Great Ships are Citadel of Spring, Column of Summer, Tower of Autumn, and Spire of Winter.