The Colony is a large biomechanical structure similar in composition to the basestars. After the Cimtar Peace Accord, the Final Five and the Cylon Centurion Model 0005 units (with the exception of the Guardians) retreated to this place, a spaceborne Cylon homeworld.
This structure was built around the original ship of the Final Five (Islanded in a Stream of Stars podcast). The vessel was used by Samuel Anders, Tory Foster, Ellen Tigh, Saul Tigh and Galen Tyrol to travel to the Twelve Colonies from the devastated remains of Earth, backtracking the path their ancestors had taken from Kobol and then following the path of the twelve tribes of humanity. At one point, the ship stopped at The Temple of Hopes.
The expanded structure was "home" to the humanoid and Centurion Cylons after the war. The eight numbered humanoid models were presumably developed by Anders, Foster, the Tighs and Tyrol here. Their original resurrection equipment was still on the Colony, as was their original sublight starship.
When the Cylons prepared to attack the Colonies, they gathered their massive fleet here and jumped directly from The Colony to the Twelve Colonies.
The Colony fell into the hands of the Number Ones/Cavils after they usurped the Final Five. Prior to the Cylon Civil War, Cavil keeps the Colony secret. Cavil moves the Colony shortly before the start of the civil war, indicating that the structure is FTL-capable. It is positioned in a stable orbit inside the accretion disc of a naked singularity.
The Colony serves as home base for the Ones, Fours, Fives, and Boomer. Hera Agathon is brought to the Colony for experimentation, to determine what makes her a successful human-Cylon hybrid and replicate it.
There are both original-model Cylon Raiders (mechanical fighter craft which require pilots) and the newer autonomous Raider models inside the Colony, and both 0005 and updated Centurion units. The Colony's systems are controlled by multiple Hybrids. It is armed with a large array of quad barreled point defense, and single barreled heavy gun batteries.
The Colony is destroyed when Margaret Edmonson's corpse inadvertantly launches several nukes at it from her Raptor, causing massive damage and the loss of its stable orbit around the singularity.
The final battle between humans and Cylons, the Battle of The Colony, takes place here when Galactica launches a rescue mission for Hera Agathon. Among the dead in the battle are numerous Centurions, at least three Dorals, three Simons, Cavil and Boomer, as well as any who are onboard the structure when it falls into the black hole.
