Tayari Plaza (achievement)
From Halopedia, the Halo wiki
Tayari Plaza
Tayari Plaza is an Achievement in Halo 3: ODST. It is awarded for completing the level Tayari Plaza in Campaign on at least normal difficulty and unlocking the Buck character for use in Firefight. It is worth 30 Gamerpoints.[1]
It is represented by an olive circle with the Marathon symbol imprinted in it, with Dare's cracked Recon helmet in front of it.
Sources