506th Tank Regiment
From Halopedia, the Halo wiki
The 506th Tank Regiment is a UNSC Marine Corps armored unit [1]
Background
The 506th fought during the Second Battle of Earth, and two smaller battles at Voi and New Mombasa.
During the Battle of Mombasa they were charged with making a path to the Southern Bridge Span, despite overwhelming forces in their path. They successfully achieved their mission.
Several years later, the Regiment's actions were honored as several replicas of the 506th's tanks were included in the John-117 Memorial at the Museum of Humanity.