Basin

Basin is a Halo 5: Guardians multiplayer map that was released on November 18, 2015 as part of the Battle of Shadow and Light update. The map is a spiritual successor to Blood Gulch and Valhalla, and was created from the Forge map Alpine. It is set in a rocky canyon with two UNSC bases at either end.

The simulation itself is loosely based on the ONI Research Facilities that were set up by the UNSC on Gamma Halo after the ring's discovery in 2553. It has been noted that Spartan-IVs trained on Basin in 2558, in preparation for the coming war against the Created and their Guardians.