From Halopedia, the Halo wiki

Ah, I'm just writing this out of boredom. Maybe someone'll be interested. I dunno. I'll try to add screenshots soon.
The Bunker
Epilogueaspawn.jpg
Map overview

Game:

Halo 3

Location:

Traxus Factory Complex 09
Voi, Kenya

Terrain:

Industrial; a small stronghold in a warehouse.

Gameplay overview

Recommended number of players:

2-6

Recommended gametype(s):

 
A bunker inside of a warehouse? How odd.

The Bunker is a multiplayer map variant of Foundry, created by User:DavidJCobb in Halo 3's Forge; it can be downloaded from his File Share. The level takes the form of a damaged, makeshift bunker located, oddly enough, inside a warehouse.

Layout

The Bunker is an asymmetric map featuring a damaged, worn, two-floored structure at its center. A ring of empty space surrounds the structure, with lines of concrete barriers placed some distance from the structure. In asymmetric team games, Foundry's two alcoves function as stockpiles for weapons and equipment.

Bunker, first floor

The eponymous bunker is a worn, decaying structure. The first floor is effectively separated into two halves, such that a vehicle can drive straight through the gap at the center. The larger of the two halves has two entrances from the ground: an open shipping container with instantly-respawning wooden palettes covering it, and a broken wall covered by a hastily-erected Shield Door. The smaller part of the first floor has only one entrance, covered with a shield door and adorned with a Shotgun.

The larger of the first floors is filled with several twists and corners. Fusion Coils are placed in one corner to balance camping, and windows on one side (at the gap between the first floors) offer a way to fire upon players that decide to camp in the largest part of the floor. Battle Rifles, Magnums, and SMGs can be found here, and two Maulers lie just outside the shield barrier.

Bunker, second floor

The first floors are connected by their shared second floor. The second floor is much more open, and contains weapon holders for ranged items, such as Battle Rifles and Carbines. Gaps in the walls allow for an easy escape from the base, and a well-positioned turret offers a perfect view of the Back Alley.

Bunker, roof

The bunker's roof is partially collapsed, with more than half of it completely gone. A section has fallen, acting as a ramp to the top. Here, a dumpster may be used as a stepping stone to climb onto a shipping container, where the level's Sniper Rifle may be found. The rifle is in full view of the front of the level.

Outside

The space outside the bunker is very wide and open. Multiple Warthogs are scattered throughout. Concrete barriers make it possible for players on foot to survive, albeit for only a short time. Battle Rifles are scattered around the area, and a Brute Shot lies near one of the alcoves. The outside region behind the bunker is known as the "Back Alley".

In asymmetric gametypes, the two alcoves act as weapons caches, containing numerous weapons and equipment items to be used for capturing the base. Among other things, Grav Lifts and Bubble Shields are stockpiled.