The drill grounds was a deleted building type in the game Halo Wars. It is possibly where the player would receive resources or upgrade Marines. Without this building, the player could not gain troops or build buildings. It is possible to see some troops doing push-ups at the rear of the building during the first Halo Wars demo. In gameplay from Halo Wars, it is not present, and is considered cut material.
While developing the Halo games, Bungie, 343 Industries and Ensemble Studios have had to cut some content, such as vehicles, gameplay, and story elements, from the final products. Much of this content has been confirmed by videos and commentary in special edition DVDs, interviews with developers, and released concept art.