Sierra 117 is an infection remake of the final segment of the Halo 3 mission SIERRA 117. It is an asymmetrical map and a mostly to-scale remake of the original. There are lots of hiding spots and decent cover for the infected and lots of opportunities for the humans to explore. Many details have been carried over from Halo 3 and it should feel pretty familiar to play in and hopefully nostalgic too.
If you don't remember the mission it's the Hydro plant where you rescue Johnson, fight a chieftain, and leave on a pelican after it blows up some phantoms. In terms of narrative, the map is set Post-War and is still operational if not slightly run down.
This map is currently in final testing phases and looking for feedback on weapons and spawns.
(Note that fog has been turned off for screenshot purposes, in the actual map there is some slight near fog and thick distance fog.)
Some screenshots from Halo 3 for comparison:
I have the images side by side in this tumblr post if you want to switch between them more easily.
Enjoy!