Oan Citadel (Earth-6531)

The Oan Citadel is the home to the Guardians of the Universe at the center of Oa.

History
Following the death of Abin Sur by Parallax, Thaal Sinestro arrived at the Oan Citadel to question the Guardians of the Universe about what had been unleashed from Ryut. The Guardians then recalled the history of Parallax, and how Sur had defeated him centuries before.

After Hal Jordan was brought to Oa via the power of his new ring, Sinestro brought him to the Citadel, where he taught Jordan about the Corps, and granted him an audition with the Guardians. The Guardians, however, showed no interest on the human when he proposed fighting Parallax.