Oa
The heart of the Green Lantern Corps — the oldest planet in the universe.
Oa sits at the center of the universe — or so the Guardians claim, and few argue with beings ten billion years old. This barren, ancient world is the headquarters of the Green Lantern Corps: the Central Power Battery rises from its surface like a green sun, and the Sciencells beneath it hold the universe's most dangerous prisoners.
Every Green Lantern's journey leads here. Recruits are summoned to Oa, trained by veterans like Kilowog, and sent out to their sectors from its launch bays. The Guardians' citadel overlooks it all — cold, blue, and impossibly old. When the Corps falls, it falls here; when it rises, it rises here too.
First appearanceGreen Lantern (vol. 2) #1 (1960)
Notable featuresCentral Power Battery, the Sciencells, the Guardians' citadel
StatusActive — rebuilt after every catastrophe